articles

2025

1. 

   Color variation in radio-luminescence of P-dots doped with thermally activated delayed fluorescence molecules

   Zheming Su, Hieu Thi Minh Nguyen, Zuoyue Liu, Daiki Asanuma, Minoru Yamaji, Masanori Koshimizu, Hajime Shigemitsu, Sachiko Tojo, Tadashi Mori, Toshiyuki Kida, Guillem Pratx^*, Mamoru Fujitsuka^*, and Yasuko Osakada^*

   Phys. Chem. Chem. Phys., 2025, 27, 7605–7610.

   Article Abs DOI Bib

   Thermally activated delayed fluorescence (TADF) materials possess exceptional photophysical properties. Organic scintillators utilizing TADF materials have shown great promise for applications requiring efficient radio-luminescence, owing to their high quantum efficiency and tunable emission properties. Previous studies demonstrated that polymer dots (P-dots) doped with TADF materials exhibit radio-luminescence under hard X-ray and electron beam excitation. However, the TADF materials used in these experiments were limited to limited color options, restricting their utility and hindering the exploration of multicolor radio-luminescence necessary for advanced applications. In this study, we successfully achieved multicolor radio-luminescence-blue, yellow, and red-by developing P-dots doped with TADF materials that emit across the visible spectrum. This breakthrough was demonstrated under excitation by hard X-rays, gamma rays, and electron beams. The ability to realize multicolor radio-luminescence is crucial, as it enables enhanced spatial and spectral resolution, which is vital for applications such as high-precision bio-imaging and multimodal sensing.

   @article{su2025color,
     title = {Color variation in radio-luminescence of P-dots doped with thermally activated delayed fluorescence molecules},
     author = {Su, Zheming and Nguyen, Hieu Thi Minh and Liu, Zuoyue and Asanuma, Daiki and Yamaji, Minoru and Koshimizu, Masanori and Shigemitsu, Hajime and Tojo, Sachiko and Mori, Tadashi and Kida, Toshiyuki and Pratx, Guillem and Fujitsuka, Mamoru and Osakada, Yasuko},
     journal = {Phys. Chem. Chem. Phys.},
     volume = {27},
     number = {15},
     pages = {7605--7610},
     year = {2025},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d5cp00410a},
     url = {https://doi.org/10.1039/d5cp00410a},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Highly emissive and robust diarylethene fluorophore incorporating imide-fused phenanthryl moieties

   Keito Nose, Minoru Yamaji, Tadashi Mori, Fumito Tani, Kenta Goto, and Hideki Okamoto^*

   Chem. Lett., 2025, 54, upaf091.

   Article Abs DOI Bib

   The fluorescence properties and photostabilities of (E)-diarylethenes (DPEs), featuring two 3-phenanthryl moieties, were investigated. Pristine (E)-di-1,2-(3-phenanthryl)ethene and its ester derivative, respectively referred to as DPE-H and DPE-E, exhibited blue fluorescence. However, they underwent a two-step photoreaction sequence that yielded [7]helicenes, resulting in a gradual reduction of the fluorescence intensity. In contrast, the imide-fused derivative DPE-I displayed intense green fluorescence and it was unexpectedly photostable in solution, maintaining its highly efficient fluorescent nature even after prolonged light exposure. DPE-I, thus, provides a new type of highly efficient and robust diarylethene fluorophore.

   @article{nose2025highly,
     title = {Highly emissive and robust diarylethene fluorophore incorporating imide-fused phenanthryl moieties},
     author = {Nose, Keito and Yamaji, Minoru and Mori, Tadashi and Tani, Fumito and Goto, Kenta and Okamoto, Hideki},
     journal = {Chem. Lett.},
     volume = {54},
     number = {5},
     pages = {upaf091},
     year = {2025},
     publisher = {Oxford University Press UK},
     doi = {10.1093/chemle/upaf091},
     url = {https://doi.org/10.1093/chemle/upaf091},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Inversion of circularly polarized luminescence by electric current flow during transition

   Ayumi Imayoshi^*, Shinya Fujio, Yuuki Nagaya, Misato Sakai, Atsushi Terazawa, Misa Sakura, Keita Okada, Takahiro Kimoto, Tadashi Mori, Yoshitane Imai, Masahiko Hada, and Kazunori Tsubaki^*

   Phys. Chem. Chem. Phys., 2025, 27, 77–82.

   Article Abs DOI Bib

   The development of chiral compounds exhibiting circularly polarized luminescence (CPL) has advanced remarkably in recent years. Designing CPL-active compounds requires an understanding of the electric transition dipole moment (μ) and the magnetic transition dipole moment (m) in the excited state. However, while the direction and magnitude of μ can, to some extent, be visually inferred from chemical structures, m remains elusive, posing challenges for direct predictions based on structural information. This study utilized binaphthol, a prominent chiral scaffold, and achieved CPL-sign inversion by strategically varying the substitution positions of phenylethynyl (PE) groups on the binaphthyl backbone, while maintaining consistent axial chirality. Theoretical investigation revealed that the substitution position of PE groups significantly affects the orientation of m in the excited state, leading to CPL-sign inversion. Furthermore, we propose that this CPL-sign inversion results from a reversal in the rotation of instantaneous current flow during the S1 → S0 transition, which in turn alters the orientation of m. The current flow can be predicted from the chemical structure, allowing anticipation of the properties of m and, consequently, the characteristics of CPL. This insight provides a new perspective in designing CPL-active compounds, particularly for C2-symmetric molecules where the S1 -> S0 transition predominantly involves LUMO → HOMO transitions. If μ represents the directionality of electron movement during transitions, i.e., the “difference” in electron locations before and after transitions, then m could be represented as the “path” of electron movement based on the current flow during the transition.

   @article{imayoshi2025inversion,
     title = {Inversion of circularly polarized luminescence by electric current flow during transition},
     author = {Imayoshi, Ayumi and Fujio, Shinya and Nagaya, Yuuki and Sakai, Misato and Terazawa, Atsushi and Sakura, Misa and Okada, Keita and Kimoto, Takahiro and Mori, Tadashi and Imai, Yoshitane and Hada, Masahiko and Tsubaki, Kazunori},
     journal = {Phys. Chem. Chem. Phys.},
     volume = {27},
     number = {1},
     pages = {77--82},
     year = {2025},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d4cp02968b},
     url = {https://doi.org/10.1039/d4cp02968b},
     dimensions = {true},
     tab = {paper},
   }

2024

1. 

   Significance of Vibronic Coupling that Shapes Circularly Polarized Luminescence of Double Helicenes

   Tadashi Mori^*

   Angew. Chem. Int. Ed., 2024, 63, e202402960.

   Article Abs DOI Bib

   The circularly polarized luminescence (CPL) spectra of S- and X-shaped double helicenes exhibit distinct vibrational structures and overall shape variations. In this study, we conducted an in-depth investigation into the vibronic effects influencing the CPL spectra of two double helicenes, namely DPC and DNH. Employing state-of-the-art computations utilizing the FC-HT1|VH model at the CAM−B3LYP/def2-TZVP level, we unveiled the paramount impact of Franck–Condon (FC), Herzberg-Teller (HT), and Duschinsky effects on their chiroptical responses. Our research underscores the pivotal role of structural deformations associated with the S1-to-S0 electronic transition in molding CPL spectra and wavelength-dependent dissymmetry (g) factor values, as well as the significance of HT effects in shaping and enhancing CPL responses. This extensive investigation not only advances our comprehension of the vibronic characteristics in configurationally distinct double helicenes but also offers valuable insights for the design of chiral molecules featuring controllable or finely-tunable CPL responses.

   @article{mori2024significance,
     title = {Significance of Vibronic Coupling that Shapes Circularly Polarized Luminescence of Double Helicenes},
     author = {Mori, Tadashi},
     journal = {Angew. Chem. Int. Ed.},
     volume = {63},
     number = {16},
     pages = {e202402960},
     year = {2024},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.202319702},
     url = {https://doi.org/10.1002/anie.202319702},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Solvatochromism and halochromism in nitro lophine derivatives: Photophysical study, computational calculations and applications as pH sensing material

   Shiv R Desai, Rinkal B Bhoraniya, Mahesh Koladiya, Vidhi V Bhopekar, Chintan R Patel, Tadashi Mori, and Sachin G Modha^*

   J. Photochem. Photobiol. A: Chem., 2024, 455, 115751.

   Article Abs DOI Bib

   Nitro Lophines were readily synthesized via multicomponent reaction of benzil, nitro benzaldehyde and ammonium acetate. All three nitro Lophines were isolated in good yields and were also characterized by various analytical and spectroscopic techniques. A distinctive solvatochromism was observed in case of ortho and para nitro containing Lophines in their absorbance spectra. In particular, naked eye solvatochromism was observed, in case of para nitro Lophine, in the form of yellow and red coloured solution in methanol and DMSO respectively. Halochromism studies revealed the hypsochromic shift under acidic pH while bathochromic shift under alkaline pH for both nitro Lophines. Again the para nitro Lophine demonstrated wonderful distinctive colour change under acidic and alkaline pH in both methanol and DMSO as solvents. The measurement of absorbance at different pH values was carried out and the data obtained were used for calculation of dissociation constants employing several graphical methods. Computational calculations were carried out using TD-DFT for UV–Vis absorption calculation while graph-convolutional neural network model was utilized for calculation of dissociation constants. Ultimately, a reusable naked eye pH detection paper could be developed using para nitro Lophine as a sole indicator.

   @article{desai2024solvatochromism,
     title = {Solvatochromism and halochromism in nitro lophine derivatives: Photophysical study, computational calculations and applications as pH sensing material},
     author = {Desai, Shiv R and Bhoraniya, Rinkal B and Koladiya, Mahesh and Bhopekar, Vidhi V and Patel, Chintan R and Mori, Tadashi and Modha, Sachin G},
     journal = {J. Photochem. Photobiol. A: Chem.},
     volume = {455},
     pages = {115751},
     year = {2024},
     publisher = {Elsevier},
     doi = {10.1016/j.jphotochem.2024.115751},
     url = {https://doi.org/10.1016/j.jphotochem.2024.115751},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Supramolecular nanosheet formation-induced photosensitisation mechanism change of Rose Bengal dye in aqueous media

   Asuka Bunno, Hajime Shigemitsu^*, Aya Yoshikawa, Yasuko Osakada, Mamoru Fujitsuka, Fumitaka Ishiwari, Akinori Saeki, Kei Ohkubo, Tadashi Mori, and Toshiyuki Kida^*

   Chem. Commun., 2024, 60, 889–892.

   Article Abs DOI Bib

   Development of two-dimensional materials and exploration of their functionalities are significant challenges due to their potential. In this study, we successfully fabricated a supramolecular nanosheet composed of amphiphilic Rose Bengal dyes in an aqueous medium. Furthermore, we elucidated a distinct change in the photosensitisation mechanism induced by nanosheet formation.

   @article{bunno2024supramolecular,
     title = {Supramolecular nanosheet formation-induced photosensitisation mechanism change of Rose Bengal dye in aqueous media},
     author = {Bunno, Asuka and Shigemitsu, Hajime and Yoshikawa, Aya and Osakada, Yasuko and Fujitsuka, Mamoru and Ishiwari, Fumitaka and Saeki, Akinori and Ohkubo, Kei and Mori, Tadashi and Kida, Toshiyuki},
     journal = {Chem. Commun.},
     volume = {60},
     number = {7},
     pages = {889--892},
     year = {2024},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d3cc05731c},
     url = {https://doi.org/10.1039/d3cc05731c},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Impact of Symmetry on Chiroptical Properties of Double Helicenes

   Tadashi Mori^*

   Symmetry, 2024, 35, 337–338.

   Article Abs DOI Bib

   The significance of chiral molecules in advanced materials and technologies is undeniable in chemistry yet designing them with desired chiroptical properties lacks reliable strategies.

   @article{mori2024impact,
     title = {Impact of Symmetry on Chiroptical Properties of Double Helicenes},
     author = {Mori, Tadashi},
     journal = {Symmetry},
     volume = {35},
     issue = {3},
     pages = {337--338},
     year = {2024},
     publisher = {Symmetry: Culture and Science},
     doi = {10.26830/symmetry_2024_3_337},
     url = {https://doi.org/10.26830/symmetry_2024_3_337},
     dimensions = {true},
     tab = {paper},
   }

2023

1. 

   Pressure-responsive polymer chemosensors for hydrostatic-pressure-signal detection: poly-L-lysine–pyrene conjugates

   Soshi Wakako, Yumiko Hori, Tomokazu Kinoshita, Takao Saiki, Xinyi Qi, Koki Hasegawa, Yoshitane Imai, Tadashi Mori, Keiichi Nakagawa, and Gaku Fukuhara^*

   ACS Macro Lett., 2023, 12, 1389–1395.

   Article Abs DOI Bib

   Stimulus-responsive polymer materials are an attractive alternative to conventional supramolecular and polymer assemblies for applications in sensing, imaging, and drug-delivery systems. Herein, we synthesized a series of pyrene-labeled α- and ε-poly-l-lysine conjugates with varying degrees of substitution (DSs). Hydrostatic-pressure-UV/vis, fluorescence, and excitation spectroscopies and fluorescence lifetime measurements revealed ground-state conformers and excited-state ensembles emitting fluorescence with variable intensities. The polylysine-based chemosensors demonstrated diverse ratiometric responses to hydrostatic pressure through adjustments in polar solvents, DSs, and polymer backbones. Additionally, the fluorescence chemosensor exhibited a promising glum value of 3.2 × 10–3, indicating potential applications in chiral fluorescent materials. This study offers valuable insights into the development of smart hydrostatic-pressure-responsive polymer materials.

   @article{wakako2023pressure,
     title = {Pressure-responsive polymer chemosensors for hydrostatic-pressure-signal detection: poly-L-lysine--pyrene conjugates},
     author = {Wakako, Soshi and Hori, Yumiko and Kinoshita, Tomokazu and Saiki, Takao and Qi, Xinyi and Hasegawa, Koki and Imai, Yoshitane and Mori, Tadashi and Nakagawa, Keiichi and Fukuhara, Gaku},
     journal = {ACS Macro Lett.},
     volume = {12},
     number = {10},
     pages = {1389--1395},
     year = {2023},
     publisher = {ACS Publications},
     doi = {10.1021/acsmacrolett.3c00427},
     url = {https://doi.org/10.1021/acsmacrolett.3c00427},
     dimensions = {true},
     tab = {paper},
   }

2. 

   A π-extended phenanthrene-fused aza [7] helicenium as a novel chiroptically-active architecture in organic and aqueous media

   Céline Olivier^*, Nao Nagatomo, Tadashi Mori, Nathan McClenaghan, Gediminas Jonusauskas, Brice Kauffmann, Yutaka Kuwahara, Makoto Takafuji, Hirotaka Ihara, and Yann Ferrand^*

   Org. Chemi. Front., 2023, 10, 752–758.

   Article Abs DOI Bib

   The synthesis and characterization of an original π-extended cationic azahelicene is reported. The phenanthrene-fused aza[7]helicene derivative encompasses a total of ten aromatic fused rings leading to a dissymmetric yet helically folded structure, as revealed by NMR and X-ray diffraction analyses. The polyaromatic and cationic nature of the new azahelicenium makes it soluble in both organic and aqueous media, which allowed photophysical studies in solvents of different polarities. The extended chromophoric species demonstrates a broad absorption over the whole visible range and orange-red fluorescence emission. Chiral resolution of the racemate was performed subsequently, affording two optically pure and configurationally stable azahelicenium enantiomers. Multi-band circular dichroism and long-wavelength circularly polarized emission were observed, associated with remarkable absorption and luminescence dissymmetry factors, both in organic and aqueous media.

   @article{olivier2023pi,
     title = {A π-extended phenanthrene-fused aza [7] helicenium as a novel chiroptically-active architecture in organic and aqueous media},
     author = {Olivier, Céline and Nagatomo, Nao and Mori, Tadashi and McClenaghan, Nathan and Jonusauskas, Gediminas and Kauffmann, Brice and Kuwahara, Yutaka and Takafuji, Makoto and Ihara, Hirotaka and Ferrand, Yann},
     journal = {Org. Chemi. Front.},
     volume = {10},
     number = {3},
     pages = {752--758},
     year = {2023},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d2qo01942f},
     url = {https://doi.org/10.1039/d2qo01942f},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Induction of chirality in the charge transfer complex photochemistry

   Tadashi Mori^*

   J. Photochem. Photobiol., 2023, 17, 100200.

   Article Abs DOI Bib

   Electron donor and acceptor undergo association in solution to form a weak molecular complex, namely a charge transfer complex. The formation of the complex is apparent by its new low-energy absorption band. Upon photoexcitation of this charge transfer band, an intracomplex electron transfer is facilitated to form a contact ion radical pair. The theoretical basis for the complex formation and the subsequent photoinduced electron transfer process has been well established already half a century ago. Nevertheless, the charge transfer complex photochemistry is now in a renaissance, due to its synthetic utility of its radical ion pair. By intentionally sidestepped unproductive back electron transfer process, a desired product is effectively obtained with or without external reagent and/or catalyst. In addition, the photoexcitation of the complex does not require any additional photocatalyst and often conceivable with the visible light. Accordingly, various donor/acceptor pairs and synthetic applications have been emerged as novel photoreaction systems in the last two decades. Some have also addressed the stereoselective transformations. This mini review highlights the recent progress of the asymmetric photoreaction, in particular in synthetic applications, based on the photoexcitation of the charge transfer complex, in comparison with photoredox catalysis.

   @article{mori2023induction,
     title = {Induction of chirality in the charge transfer complex photochemistry},
     author = {Mori, Tadashi},
     journal = {J. Photochem. Photobiol.},
     volume = {17},
     pages = {100200},
     year = {2023},
     publisher = {Elsevier},
     doi = {10.1016/j.jpap.2023.100200},
     url = {https://doi.org/10.1016/j.jpap.2023.100200},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Radioluminescence from polymer dots based on thermally activated delayed fluorescence

   Daiki Asanuma, Hieu Thi Minh Nguyen, Zuoyue Liu, Sachiko Tojo, Hajime Shigemitsu, Minoru Yamaji, Kiyohiko Kawai, Tadashi Mori, Toshiyuki Kida, Guillem Pratx^*, Mamoru Fujitsuka^*, and Yasuko Osakada^*

   Nanoscale Adv., 2023, 5, 3424–3427.

   Article Abs DOI Bib

   We demonstrate that polymer dots doped with thermally activated delayed fluorescence (TADF) molecules clearly exhibit blue radio-luminescence upon hard X-ray and electron beam irradiation, which is a new design for nano-sized scintillators.

   @article{asanuma2023radioluminescence,
     title = {Radioluminescence from polymer dots based on thermally activated delayed fluorescence},
     author = {Asanuma, Daiki and Nguyen, Hieu Thi Minh and Liu, Zuoyue and Tojo, Sachiko and Shigemitsu, Hajime and Yamaji, Minoru and Kawai, Kiyohiko and Mori, Tadashi and Kida, Toshiyuki and Pratx, Guillem and Fujitsuka, Mamoru and Osakada, Yasuko},
     journal = {Nanoscale Adv.},
     volume = {5},
     number = {13},
     pages = {3424--3427},
     year = {2023},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d3na00308f},
     url = {https://doi.org/10.1039/d3na00308f},
     dimensions = {true},
     tab = {paper},
   }

2022

1. 

   Fluorescein-Based Type I Supramolecular Photosensitizer via Induction of Charge Separation by Self-Assembly

   Hajime Shigemitsu^*, Kei Ohkubo, Kazuhide Sato, Asuka Bunno, Tadashi Mori, Yasuko Osakada, Mamoru Fujitsuka, and Toshiyuki Kida^*

   JACS Au, 2022, 2, 1472–1478.

   Article Abs DOI Bib

   Photosensitizers (PSs) are critical substances with considerable potential for use in non-invasive photomedicine. Type I PSs, which generate reactive radical species by electron transfer from the excited state induced via photoirradiation, attracted much attention because of their suitability for photodynamic therapy (PDT) irrespective of the oxygen concentration. However, most organic PSs are type II, which activates only oxygen, generating singlet oxygen (1O2) via energy transfer from the triplet state. Here, we proposed a strategy to form type I supramolecular PSs (SPSs) utilizing the charge-separated state induced by self-assembly. This was demonstrated using a supramolecular assembly of fluorescein, which is a type II PS in the monomeric state; however, it changes to a type I SPS via self-assembly. The switching mechanism from type II to I via self-assembly was clarified using photophysical and electrochemical analyses, with the type I SPS exhibiting significant PDT effects on cancer cells. This study provides a promising approach for the development of type I PSs based on supramolecular assemblies.

   @article{shigemitsu2022fluorescein,
     title = {Fluorescein-Based Type I Supramolecular Photosensitizer via Induction of Charge Separation by Self-Assembly},
     author = {Shigemitsu, Hajime and Ohkubo, Kei and Sato, Kazuhide and Bunno, Asuka and Mori, Tadashi and Osakada, Yasuko and Fujitsuka, Mamoru and Kida, Toshiyuki},
     journal = {JACS Au},
     volume = {2},
     issue = {6},
     pages = {1472--1478},
     year = {2022},
     month = may,
     publisher = {ACS Publications},
     doi = {10.1021/jacsau.2c00243},
     url = {https://doi.org/10.1021/jacsau.2c00243},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Visible Light-Induced Regio-and Enantiodifferentiating [2+2] Photocycloaddition of 1, 4-Naphthoquinones Mediated by Oppositely Coordinating 1, 3, 2-Oxazaborolidine Chiral Lewis Acid

   Nao Shimizu, Hajime Shigemitsu, Toshiyuki Kida, Thorsten Bach, and Tadashi Mori^*

   J. Org. Chem., 2022, 87, 8071–8083.

   Article Abs DOI Bib

   A range of asymmetric photochemical transformations using visible light have recently become considerably attractive. Among the various approaches, chiral Lewis acid association to enones for [2 + 2] and ortho photocycloadditions and oxadi-π-methane rearrangements have shown to be very promising. Naturally, chiral Lewis acid coordination protects one of the prochiral faces of the C═C double bond, which enables an effective enantiodifferentiation in the following bond-forming process(es). Here, we studied regio- and enantiodifferentiating [2 + 2] photocycloaddition reactions of naphthoquinone derivatives mediated by chiral oxazaborolidines. A stereochemical control was quite challenging for the 2-ene-1,4-dione substrate, as a double coordination of Lewis acid essentially cancels out the face selectivity, and a mono-coordination to each carbonyl group leads to an opposite stereochemical outcome. Furthermore, a stepwise coordination in the ground state of Lewis acid in a 1:1 fashion was practically inaccessible. We found that the excited-state decomplexation is a key to accomplish high regio- and enantioselectivities in the photocycloaddition of an ene-dione.

   @article{shimizu2022visible,
     title = {Visible Light-Induced Regio-and Enantiodifferentiating [2+2] Photocycloaddition of 1, 4-Naphthoquinones Mediated by Oppositely Coordinating 1, 3, 2-Oxazaborolidine Chiral Lewis Acid},
     author = {Shimizu, Nao and Shigemitsu, Hajime and Kida, Toshiyuki and Bach, Thorsten and Mori, Tadashi},
     journal = {J. Org. Chem.},
     volume = {87},
     issue = {12},
     pages = {8071--8083},
     year = {2022},
     publisher = {ACS Publications},
     doi = {10.1021/acs.joc.2c00730},
     url = {https://doi.org/10.1021/acs.joc.2c00730},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Controlling anisotropic properties by manipulating the orientation of chiral small molecules

   Jessica Wade^*, Francesco Salerno, Rachel C Kilbride, Dong Kuk Kim, Julia A Schmidt, Joel A Smith, Luc M LeBlanc, Emma H Wolpert, Adebayo A Adeleke, Erin R Johnson, Jenny Nelson, Tadashi Mori, Kim E Jelfs, Sandrine Heutz, and Matthew J Fuchter^*

   Nat. Chem., 2022, 14, 1383–1389.

   Article Abs DOI Bib

   Chiral π-conjugated molecules bring new functionality to technological applications and represent an exciting, rapidly expanding area of research. Their functional properties, such as the absorption and emission of circularly polarized light or the transport of spin-polarized electrons, are highly anisotropic. As a result, the orientation of chiral molecules critically determines the functionality and efficiency of chiral devices. Here we present a strategy to control the orientation of a small chiral molecule (2,2′-dicyano[6]helicene) by the use of organic and inorganic templating layers. Such templating layers can either force 2,2′-dicyano[6]helicene to adopt a face-on orientation and self-assemble into upright supramolecular columns oriented with their helical axis perpendicular to the substrate, or an edge-on orientation with parallel-lying supramolecular columns. Through such control, we show that low- and high-energy chiroptical responses can be independently ‘turned on’ or ‘turned off’. The templating methodologies described here provide a simple way to engineer orientational control and, by association, anisotropic functional properties of chiral molecular systems for a range of emerging technologies.

   @article{wade2022controlling,
     title = {Controlling anisotropic properties by manipulating the orientation of chiral small molecules},
     author = {Wade, Jessica and Salerno, Francesco and Kilbride, Rachel C and Kim, Dong Kuk and Schmidt, Julia A and Smith, Joel A and LeBlanc, Luc M and Wolpert, Emma H and Adeleke, Adebayo A and Johnson, Erin R and Nelson, Jenny and Mori, Tadashi and Jelfs, Kim E and Heutz, Sandrine and Fuchter, Matthew J},
     journal = {Nat. Chem.},
     volume = {14},
     number = {12},
     pages = {1383--1389},
     year = {2022},
     publisher = {Nature Publishing Group UK London},
     doi = {10.1038/s41557-022-01044-6},
     url = {https://doi.org/10.1038/s41557-022-01044-6},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Amphiphilic rhodamine nano-assembly as a type I supramolecular photosensitizer for photodynamic therapy

   Hajime Shigemitsu^*, Kazuhide Sato, Satomi Hagio, Youhei Tani, Tadashi Mori, Kei Ohkubo, Yasuko Osakada, Mamoru Fujitsuka, and Toshiyuki Kida^*

   ACS Appl. Nano Mater., 2022, 5, 14954–14960.

   Article Abs DOI Bib

   Photodynamic therapy (PDT) is a promising clinical method for treating a wide range of cancers. Recently, PDT employing type I photosensitizers (PSs) has attracted considerable attention owing to the feasibility of efficient PDT under hypoxic conditions. Particularly, type I supramolecular PSs (SPSs) are promising candidates owing to their functional extensibility by facile hybridization. However, type I SPSs are rare, and the development strategy has not been established yet. In this work, we demonstrated that supramolecular assembly of a simple amphiphilic rhodamine 19 (Rh19-MA-C18) functioned as a type I SPS and exhibited significant PDT effect on cancer cells and cancer-bearing mice. This work demonstrates the potential of supramolecular nano-assembly composed of an amphiphilic rhodamine dye as an efficient type I SPS.

   @article{shigemitsu2022amphiphilic,
     title = {Amphiphilic rhodamine nano-assembly as a type I supramolecular photosensitizer for photodynamic therapy},
     author = {Shigemitsu, Hajime and Sato, Kazuhide and Hagio, Satomi and Tani, Youhei and Mori, Tadashi and Ohkubo, Kei and Osakada, Yasuko and Fujitsuka, Mamoru and Kida, Toshiyuki},
     journal = {ACS Appl. Nano Mater.},
     volume = {5},
     number = {10},
     pages = {14954--14960},
     year = {2022},
     publisher = {ACS Publications},
     doi = {10.1021/acsanm.2c03192},
     url = {https://doi.org/10.1021/acsanm.2c03192},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Cyclodextrins with multiple pyrenyl groups: an approach to organic molecules exhibiting bright excimer circularly polarized luminescence

   Hajime Shigemitsu^*, Kosei Kawakami, Yuuya Nagata, Rikuo Kajiwara, Shintaro Yamada, Tadashi Mori, and Toshiyuki Kida^*

   Angew. Chem. Int. Ed., 2022, 134, e202114700.

   Article Abs DOI Bib

   We report a simple and effective approach to organic molecules exhibiting bright circularly polarized luminescence (CPL) by combining a chiral cyclic molecular scaffold and multiple excimer-enabling moieties. An α-cyclodextrin (CyD) scaffold was modified with six pyrenyl groups to obtain pyrene–cyclodextrins (PCDs) in a one-step synthesis from commercially available compounds. The PCDs exhibited high molar extinction coefficients (ϵ≈105 M−1 cm−1), polarized emission with a good dissymmetry factor (|glum|≈10−2), and quantum yield (Φf≈0.5). Owing to the excellent photophysical properties of the PCDs, the circularly polarized luminescence brightness (BCPL) reached 340 M−1 cm−1. Photophysical and chiroptical studies of the PCDs with only five pyrene units and with linkers of various lengths connecting the CyD with the pyrene units revealed that the formation of a pyrene excimer in a spatially crowded environment is crucial for CPL anisotropy. This study paves the way for the development of bright CPL organic molecules.

   @article{shigemitsu2022cyclodextrins,
     title = {Cyclodextrins with multiple pyrenyl groups: an approach to organic molecules exhibiting bright excimer circularly polarized luminescence},
     author = {Shigemitsu, Hajime and Kawakami, Kosei and Nagata, Yuuya and Kajiwara, Rikuo and Yamada, Shintaro and Mori, Tadashi and Kida, Toshiyuki},
     journal = {Angew. Chem. Int. Ed.},
     volume = {134},
     number = {8},
     pages = {e202114700},
     year = {2022},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.202114700},
     url = {https://doi.org/10.1002/anie.202114700},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Chiroptical induction with prism [5] arene alkoxy-homologs

   Xiaotong Liang, Yanling Shen, Dayang Zhou, Jiecheng Ji, Hongtao Wang, Ting Zhao, Tadashi Mori, Wanhua Wu, and Cheng Yang

   Chem. Commun., 2022, 58, 13584–13587.

   Article Abs DOI Bib

   The complexation of prism[5]arenes with amino acid derivatives showed association constants of up to 107 M−1, significant CD with gabs of up to 0.8 × 10−2 and CPL with glum of 2 × 10−3. The absolute configuration-CD signal correlation was established. The CD spectra varied significantly with the substituents on the prism[5]arenes.

   @article{liang2022chiroptical,
     title = {Chiroptical induction with prism [5] arene alkoxy-homologs},
     author = {Liang, Xiaotong and Shen, Yanling and Zhou, Dayang and Ji, Jiecheng and Wang, Hongtao and Zhao, Ting and Mori, Tadashi and Wu, Wanhua and Yang, Cheng},
     journal = {Chem. Commun.},
     volume = {58},
     number = {98},
     pages = {13584--13587},
     year = {2022},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d2cc05690a},
     url = {https://doi.org/10.1039/d2cc05690a},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Differences in enantioselective hydroxylation of 2, 2’, 3, 6-tetrachlorobiphenyl (CB45) and 2, 2’, 3, 4’, 6-pentachlorobiphenyl (CB91) by human and rat CYP2B subfamilies

   Hideyuki Inui^*, Terushi Ito, Chiharu Miwa, Yuki Haga, Makoto Kubo, Toshimasa Itoh, Keiko Yamamoto, Masayuki Miyaoka, Tadashi Mori, Harunobu Tsuzuki, and others

   Environ. Sci. Technol., 2022, 56, 10204–10215.

   Article Abs DOI Bib

   Although polychlorinated biphenyls (PCBs) were commercially banned half a century ago, contamination of the environment and organisms by PCBs is still observed. PCBs show high persistence and bioaccumulation, resulting in toxicity. Among PCBs, chiral PCBs with more than three chlorine atoms at the ortho-position exhibit developmental and neurodevelopmental toxicity. Because toxicity is dependent on the atropisomer, atropisomer-specific metabolism is vital in determining toxicity. However, structural information on enantioselective metabolism remains elusive. Cytochrome P450 (CYP, P450) monooxygenases, particularly human CYP2B6 and rat CYP2B1, metabolize separated atropisomers of 2,2’,3,6-tetrachlorobiphenyl (CB45) and 2,2’,3,4’,6-pentachlorobiphenyl (CB91) to dechlorinated and hydroxylated metabolites. Docking studies using human CYP2B6 predict 4′-hydroxy (OH)-CB45 from (aR)-CB45 as a major metabolite of CB45. Di-OH- and dechlorinated OH-metabolites from human CYP2B6 and rat CYP2B1 are also detected. Several hydroxylated metabolites are derived from CB91 by both P450s; 5-OH-CB91 is predicted as a major metabolite. CB91 dechlorination is also detected by identifying 3-OH-CB51. A stable conformation of PCBs in the substrate-binding cavity and close distance to P450 heme are responsible for high metabolizing activities. As hydroxylation and dechlorination change PCB toxicity, this approach helps understand the possible toxicity of chiral PCBs in mammals.

   @article{inui2022differences,
     title = {Differences in enantioselective hydroxylation of 2, 2', 3, 6-tetrachlorobiphenyl (CB45) and 2, 2', 3, 4', 6-pentachlorobiphenyl (CB91) by human and rat CYP2B subfamilies},
     author = {Inui, Hideyuki and Ito, Terushi and Miwa, Chiharu and Haga, Yuki and Kubo, Makoto and Itoh, Toshimasa and Yamamoto, Keiko and Miyaoka, Masayuki and Mori, Tadashi and Tsuzuki, Harunobu and others},
     journal = {Environ. Sci. Technol.},
     volume = {56},
     number = {14},
     pages = {10204--10215},
     year = {2022},
     publisher = {ACS Publications},
     doi = {10.1021/acs.est.2c01155},
     url = {https://doi.org/10.1021/acs.est.2c01155},
     dimensions = {true},
     tab = {paper},
   }

8. Photochemistry Controlled by Weak Supramolecular Interactions

   Tadashi Mori^*

   Manufacturing and Technology, 2022, 74, 65–68.

   Bib

   @article{mori2022photochemistry,
     title = {Photochemistry Controlled by Weak Supramolecular Interactions},
     author = {Mori, Tadashi},
     journal = {Manufacturing and Technology},
     volume = {74},
     issue = {1},
     pages = {65--68},
     year = {2022}
   }

2021

1. 

   Overtemperature-protection intelligent molecular chiroptical photoswitches

   Jiabin Yao, Wanhua Wu^*, Chao Xiao, Dan Su, Zhihui Zhong, Tadashi Mori, and Cheng Yang^*

   Nat. Commun., 2021, 12, 2600.

   Article Abs DOI Bib

   Stimuli-responsive intelligent molecular machines/devices are of current research interest due to their potential application in minimized devices. Constructing molecular machines/devices capable of accomplishing complex missions is challenging, demanding coalescence of various functions into one molecule. Here we report the construction of intelligent molecular chiroptical photoswitches based on azobenzene-fused bicyclic pillar[n]arene derivatives, which we defined as molecular universal joints (MUJs). The Z/E photoisomerization of the azobenzene moiety of MUJs induces rolling in/out conformational switching of the azobenzene-bearing side-ring and consequently leads to planar chirality switching of MUJs. Meanwhile, temperature variation was demonstrated to also cause conformational/chiroptical inversion due to the significant entropy change during the ring-flipping. As a result, photo-induced chiroptical switching could be prohibited when the temperature exceeded an upper limit, demonstrating an intelligent molecular photoswitch having over-temperature protection function, which is in stark contrast to the low-temperature-gating effect commonly encountered.

   @article{yao2021overtemperature,
     title = {Overtemperature-protection intelligent molecular chiroptical photoswitches},
     author = {Yao, Jiabin and Wu, Wanhua and Xiao, Chao and Su, Dan and Zhong, Zhihui and Mori, Tadashi and Yang, Cheng},
     journal = {Nat. Commun.},
     volume = {12},
     issue = {1},
     pages = {2600},
     year = {2021},
     publisher = {Nature Publishing Group UK London},
     doi = {10.1038/s41467-021-22880-z},
     url = {https://doi.org/10.1038/s41467-021-22880-z},
     dimensions = {true},
     tab = {paper},
   }

2. 

   A cyanine dye based supramolecular photosensitizer enabling visible-light-driven organic reaction in water

   Hajime Shigemitsu^*, Tomoe Tamemoto, Kei Ohkubo, Tadashi Mori, Yasuko Osakada, Mamoru Fujitsuka, and Toshiyuki Kida

   Chem. Commun., 2021, 57, 11217–11220.

   Article Abs DOI Bib

   We report the aggregation-induced photosensitizing activity of a cyanine dye in water and the mechanism. In addition, using the supramolecular assembly, visible-light-driven photooxidation of hydrophobic aromatic compounds in water was successfully performed.

   @article{shigemitsu2021cyanine,
     title = {A cyanine dye based supramolecular photosensitizer enabling visible-light-driven organic reaction in water},
     author = {Shigemitsu, Hajime and Tamemoto, Tomoe and Ohkubo, Kei and Mori, Tadashi and Osakada, Yasuko and Fujitsuka, Mamoru and Kida, Toshiyuki},
     journal = {Chem. Commun.},
     volume = {57},
     issue = {85},
     pages = {11217--11220},
     year = {2021},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d1cc04685c},
     url = {https://doi.org/10.1039/d1cc04685c},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Synthesis, Structure, and Chiroptical Properties of Indolo-and Pyridopyrrolo-Carbazole-Based C2-Symmetric Azahelicenes

   Taisei Taniguchi, Yuji Nishii, Tadashi Mori^*, Ken-ichi Nakayama, and Masahiro Miura^*

   Chem. Eur. J., 2021, 27, 7356–7361.

   Article Abs DOI Bib

   Treatment of 11,12-bis(1,1’-biphenyl-3-yl or 6-phenylpyridin-2-yl)-substituted 11,12-dihydro-indolo[2,3-a]carbazole with an oxidizing system of Pd(II)/Ag(I) induced effective double dehydrogenative cyclization to afford the corresponding π-extended azahelicenes. The optical resolutions were readily achieved by a preparative chiral HPLC. It was found that the pyridopyrrolo-carbazole-based azahelicene that contains four nitrogen atoms exhibits ca. 6 times larger dissymmetry factors both in circularly dichroism (CD) and circularly polarized luminescence (CPL), |gCD| and |gCPL| values being 1.1×10−2 and 4.4×10−3, respectively, as compared with the parent indolocarbazole-based azahelicene. Theoretical calculations at the RI-CC2 level were employed to rationalize the observed enhanced chiroptical responses. The (chir)optical properties of the former helicene was further tuned by a protonation leading to remarkable red-shift with a considerable enhancement of the |gCPL| value.

   @article{taniguchi2021synthesis,
     title = {Synthesis, Structure, and Chiroptical Properties of Indolo-and Pyridopyrrolo-Carbazole-Based C2-Symmetric Azahelicenes},
     author = {Taniguchi, Taisei and Nishii, Yuji and Mori, Tadashi and Nakayama, Ken-ichi and Miura, Masahiro},
     journal = {Chem. Eur. J.},
     volume = {27},
     issue = {26},
     pages = {7356--7361},
     year = {2021},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.202100327},
     url = {https://doi.org/10.1002/chem.202100327},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Chiroptical properties of symmetric double, triple, and multiple helicenes

   Tadashi Mori^*

   Chem. Rev., 2021, 121, 2373–2412.

   Review Abs DOI Bib

   Helicenes have attracted considerable attention due to their inherent helical chirality and extended π-conjugation. Recently, rapid progress has been witnessed in the preparation of double, triple, quadruple, quintuple, and sextuple helicenes, where plural helicene moieties are symmetrically arranged in a single molecule. While synthetic efforts and X-ray crystallographic analyses devoted to these multiple helicenes and theoretical investigations on their isomerization and racemization behaviors have been relatively well documented and reviewed in the literature, the chiroptical properties of the multiple helicities have been somewhat overlooked. This review discourses the cumulative and systematic investigations on the chiroptical properties such as the circular dichroism (CD) and circularly polarized luminescence (CPL) of multiple helicenes. Although the number and structural variations of multiple helicenes reported to date have been fairly limited, this review overviews the current status of the chemistry of multiple helicenes from the viewpoint of chiroptical properties and provides insights into the design principle for advanced chiroptical materials through the proper arrangement of multiple helices, highlighting the impact of the molecular symmetry on the chiroptical responses.

   @article{mori2021chiroptical,
     title = {Chiroptical properties of symmetric double, triple, and multiple helicenes},
     author = {Mori, Tadashi},
     journal = {Chem. Rev.},
     volume = {121},
     issue = {4},
     pages = {2373--2412},
     year = {2021},
     publisher = {ACS Publications},
     doi = {10.1021/acs.chemrev.0c01017},
     url = {https://doi.org/10.1021/acs.chemrev.0c01017},
     dimensions = {true},
     tab = {review},
   }

2020

1. 

   Enhancing Photostability of a Coumarin Dye by Self-inclusion into a Cyclodextrin Cavity in Aqueous Solution and Living Cells

   Hajime Shigemitsu^*, Keigo Matsuda, Tadashi Mori, Hirotaka Nakatsuji, Michiya Matsusaki, and Toshiyuki Kida^*

   Asian J. Org. Chem., 2020, 9, 2112–2115.

   Article Abs DOI Bib

   Photostable organic dyes are highly demanded for longtime or super-resolution bioimaging. Herein, we demonstrate effective improvement of photostability of a coumarin dye (Pacific Blue (PB)) by steric protection using a cyclodextrin. The PB conjugated cyclodextrin (PB−CD) showed 2.8 times higher photostability than PB ethyl amide (PB−EA) which is a comparative compound in vitro. The cyclodextrin conjugation to PB not only protect PB unit from reactive chemicals, but also suppress reactive oxygen species (ROS) generation which causes dye degradation. The effects afford significant improvement of photostability of PB dye. Finally, the photostability of PB−CD was evaluated using confocal laser scanning microscopy (CLSM) and the significant improvement effect was proofed even in living cells.

   @article{shigemitsu2020enhancing,
     title = {Enhancing Photostability of a Coumarin Dye by Self-inclusion into a Cyclodextrin Cavity in Aqueous Solution and Living Cells},
     author = {Shigemitsu, Hajime and Matsuda, Keigo and Mori, Tadashi and Nakatsuji, Hirotaka and Matsusaki, Michiya and Kida, Toshiyuki},
     journal = {Asian J. Org. Chem.},
     volume = {9},
     issue = {12},
     pages = {2112--2115},
     year = {2020},
     publisher = {Wiley Online Library},
     doi = {10.1002/ajoc.202000365},
     url = {https://doi.org/10.1002/ajoc.202000365},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Relevance of the entropy factor in stereoselectivity control of asymmetric photoreactions

   Tadashi Mori^*

   Synlett, 2020, 31, 1259–1267.

   Review Abs DOI Bib

   Entropy as well as enthalpy factors play substantial roles in various chemical phenomena such as equilibrium and reactions. However, the entropy factors are frequently underestimated in most instances, particularly in synthetic chemistry. In reality, the entropy factor can be in competition with the enthalpy factor or can even be decisive in determining the overall free or activation energy change upon molecular interaction and chemical transformation, particularly where weak interactions in ground and/or excited states are significant. In this account, we overview the importance of the entropy factor in various chemical phenomena in both thermodynamics and kinetics and in the ground and excited states. It is immediately apparent that many diastereo- and enantioselective photoreactions are entropy-controlled. Recent advances on the entropy-control concept in asymmetric photoreactions are further discussed. Understanding the entropy-control concept will pave the way to improve, fine-tune, and even invert the chemo- and stereoselectivity of relevant chemical phenomena.

   @article{mori2020relevance,
     title = {Relevance of the entropy factor in stereoselectivity control of asymmetric photoreactions},
     author = {Mori, Tadashi},
     journal = {Synlett},
     volume = {31},
     issue = {13},
     pages = {1259--1267},
     year = {2020},
     publisher = {Georg Thieme Verlag},
     doi = {10.1055/s-0040-1707962},
     url = {https://doi.org/10.1055/s-0040-1707962},
     dimensions = {true},
     tab = {review},
   }

3. 

   Enantiodifferentiating Photodimerization of a 2, 6-Disubstituted Anthracene Assisted by Supramolecular Double-Helix Formation with Chiral Amines

   Akio Urushima, Daisuke Taura, Makoto Tanaka, Naomichi Horimoto, Junki Tanabe, Naoki Ousaka, Tadashi Mori, and Eiji Yashima^*

   Angew. Chem. Int. Ed., 2020, 59, 7478–7486.

   Article Abs DOI Bib

   A novel 2,6-anthrylene-linked bis(m-terphenylcarboxylic acid) strand (1) self-associates into a racemic double-helix. In the presence of chiral mono- and diamines, either a right- or left-handed double-helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face-selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo- (anti or syn) and enantiodifferentiating way to afford the chiral anti-photodimer with up to 98% enantiomeric excess when (R)-phenylethylamine was used as a chiral double-helix inducer. The resulting optically active anti-photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines.

   @article{urushima2020enantiodifferentiating,
     title = {Enantiodifferentiating Photodimerization of a 2, 6-Disubstituted Anthracene Assisted by Supramolecular Double-Helix Formation with Chiral Amines},
     author = {Urushima, Akio and Taura, Daisuke and Tanaka, Makoto and Horimoto, Naomichi and Tanabe, Junki and Ousaka, Naoki and Mori, Tadashi and Yashima, Eiji},
     journal = {Angew. Chem. Int. Ed.},
     volume = {59},
     issue = {19},
     pages = {7478--7486},
     year = {2020},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.201916103},
     url = {https://doi.org/10.1002/anie.201916103},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Figure-eight Octaphyrin Bis-Ge (IV) Complexes: Synthesis, Structures, Aromaticity, and Chiroptical Properties

   Mondo Izawa, Taisuke Suito, Shin-ichiro Ishida, Daiki Shimizu, Takayuki Tanaka^*, Tadashi Mori^*, and Atsuhiro Osuka^*

   Chem. Asian J., 2020, 15, 1440–1448.

   Article Abs DOI Bib

   Highly twisted structures of expanded porphyrin provide a prominent basis to unravel the relationship between aromaticity and chirality. Here we report the synthesis of bis-Ge(IV) complexes of [38]octaphyrin that display rigid figure-eight structures. Two bis-Ge(IV) [38]octaphyrin isomers with respect to the stereochemistry of the axial hydroxy groups on the germanium ions were obtained and found to be aromatic. Upon oxidation with MnO2, these [38]octaphyrin complexes were converted to a single syn-type isomer of [36]octaphyrin with retained figure-eight conformation. The enantiomers have been successfully separated by HPLC equipped with a chiral stationary phase. While aromatic [38]octaphyrin Ge(IV) complexes showed quite large molar circular dichroism of up to Δϵ=1500 M−1cm−1 with a dissymmetry factor gabs of 0.035, weakly antiaromatic [36]octaphyrin Ge(IV) complexes underscored moderate values; Δϵ=540 M−1cm−1 with gabs of 0.023. Thus, the figure-eight octaphyrin scaffold has been proved to be an attractive platform for novel chiroptical materials with tunable aromaticity.

   @article{izawa2020figure,
     title = {Figure-eight Octaphyrin Bis-Ge (IV) Complexes: Synthesis, Structures, Aromaticity, and Chiroptical Properties},
     author = {Izawa, Mondo and Suito, Taisuke and Ishida, Shin-ichiro and Shimizu, Daiki and Tanaka, Takayuki and Mori, Tadashi and Osuka, Atsuhiro},
     journal = {Chem. Asian J.},
     volume = {15},
     issue = {9},
     pages = {1440--1448},
     year = {2020},
     publisher = {Wiley Online Library},
     doi = {10.1002/asia.202000159},
     url = {https://doi.org/10.1002/asia.202000159},
     dimensions = {true},
     tab = {paper},
   }

5. 

   A thioxanthone sensitizer with a chiral phosphoric acid binding site: properties and applications in visible light-mediated cycloadditions

   Franziska Pecho, You-Quan Zou, Johannes Gramüller, Tadashi Mori, Stefan M Huber, Andreas Bauer, Ruth M Gschwind, and Thorsten Bach^*

   Chem. Eur. J., 2020, 26, 5190–5194.

   Article Abs DOI Bib

   A chiral phosphoric acid with a 2,2’-binaphthol core was prepared that displays two thioxanthone moieties at the 3,3’-position as light-harvesting antennas. Despite its relatively low triplet energy, the phosphoric acid was found to be an efficient catalyst for the enantioselective intermolecular [2+2] photocycloaddition of β-carboxyl-substituted cyclic enones (e.r. up to 93:7). Binding of the carboxylic acid to the sensitizer is suggested by NMR studies and by DFT calculations to occur by means of two hydrogen bonds. The binding event not only enables an enantioface differentiation but also modulates the triplet energy of the substrates.

   @article{pecho2020thioxanthone,
     title = {A thioxanthone sensitizer with a chiral phosphoric acid binding site: properties and applications in visible light-mediated cycloadditions},
     author = {Pecho, Franziska and Zou, You-Quan and Gramüller, Johannes and Mori, Tadashi and Huber, Stefan M and Bauer, Andreas and Gschwind, Ruth M and Bach, Thorsten},
     journal = {Chem. Eur. J.},
     volume = {26},
     issue = {23},
     pages = {5190--5194},
     year = {2020},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.202000720},
     url = {https://doi.org/10.1002/chem.202000720},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Combined Experimental and Theoretical Studies on Planar Chirality of Partially Overlapped C2-Symmetric [3.3](3,9)Dicarbazolophanes

   Keita Tani^*, Kanae Imafuku, Miyuki Eiraku Masaki, Haruka Kato, Kazushige Hori, Koji Kubono, Masatsugu Taneda, Takunori Harada, Kenta Goto, Fumito Tani, and Tadashi Mori^*

   J. Phys. Chem. A, 2020, 124, 2057–2063.

   Article Abs DOI Bib

   Partially overlapped dicarbazolophanes exhibit a planar chirality. In this study, C2-symmetrical [3.3](3,9)dicarbazolophane derivatives (CZ1–CZ3) have been optically resolved by preparative chiral high-performance liquid chromatography for the first time. In their circular dichroism (CD) spectra, moderate Cotton effects (CEs) were observed for their 1Lb and 1La transitions (|Δε| = 10–12 and 51–57 M–1 cm–1, respectively), while intense CEs were notified in their 1B transitions (|Δε| = 156–216 M–1 cm–1), absorption dissymmetry (gabs) factors being in orders of 10–2. Circularly polarized luminescence spectrum was also obtained for cyanamide derivative CZ1, with a comparative luminescence dissymmetry (glum) factor of 0.013. A computational investigation was applied to address the factors for such remarkable chiroptical responses in these dicarbazolophanes of planar chirality. Absolute configurations were unambiguously determined by the comparison of experimental and theoretical CD spectra, which was affirmed by the X-ray crystal structural analysis of enantiomerically pure sulfonamide derivative CZ2.

   @article{tani2020combined,
     title = {Combined Experimental and Theoretical Studies on Planar Chirality of Partially Overlapped C2-Symmetric [3.3](3,9)Dicarbazolophanes},
     author = {Tani, Keita and Imafuku, Kanae and Masaki, Miyuki Eiraku and Kato, Haruka and Hori, Kazushige and Kubono, Koji and Taneda, Masatsugu and Harada, Takunori and Goto, Kenta and Tani, Fumito and Mori, Tadashi},
     journal = {J. Phys. Chem. A},
     volume = {124},
     issue = {10},
     pages = {2057--2063},
     year = {2020},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.0c00286},
     url = {https://doi.org/10.1021/acs.jpca.0c00286},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Aggregation-induced photocatalytic activity and efficient photocatalytic hydrogen evolution of amphiphilic rhodamines in water

   Hajime Shigemitsu^*, Youhei Tani, Tomoe Tamemoto, Tadashi Mori, Xinxi Li, Yasuko Osakada, Mamoru Fujitsuka, and Toshiyuki Kida^*

   Chem. Sci., 2020, 11, 11843–11848.

   Article Abs DOI Bib

   The development of photocatalysts is an essential task for clean energy generation and establishing a sustainable society. This paper describes the aggregation-induced photocatalytic activity (AI-PCA) of amphiphilic rhodamines and photocatalytic functions of the supramolecular assemblies. The supramolecular assemblies consisting of amphiphilic rhodamines with octadecyl alkyl chains exhibited significant photocatalytic activity under visible light irradiation in water, while the corresponding monomeric rhodamines did not exhibit photocatalytic activity. The studies on the photocatalytic mechanism by spectroscopic and microscopic analyses clearly demonstrated the AI-PCA of the rhodamines. Moreover, the supramolecular assemblies of the rhodamines exhibited excellent photocatalytic hydrogen evolution rates (up to 5.9 mmol g−1 h−1).

   @article{shigemitsu2020aggregation,
     title = {Aggregation-induced photocatalytic activity and efficient photocatalytic hydrogen evolution of amphiphilic rhodamines in water},
     author = {Shigemitsu, Hajime and Tani, Youhei and Tamemoto, Tomoe and Mori, Tadashi and Li, Xinxi and Osakada, Yasuko and Fujitsuka, Mamoru and Kida, Toshiyuki},
     journal = {Chem. Sci.},
     volume = {11},
     issue = {43},
     pages = {11843--11848},
     year = {2020},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/d0sc04285d},
     url = {https://doi.org/10.1039/d0sc04285d},
     dimensions = {true},
     tab = {paper},
   }

8. 

   Irreverent nature of dissymmetry factor and quantum yield in circularly polarized luminescence of small organic molecules

   Yuya Nagata and Tadashi Mori^*

   Front. Chem., 2020, 8, 448.

   Review Abs DOI Bib

   Recently, a rational modification of small organic molecules has attracted considerable attention for designing advanced materials with enhanced circularly polarized luminescence (CPL) activity. A particular emphasis has been placed on fully allowed π-π* transition of rigid aromatic systems, due to their relatively superior emission properties or quantum yields of luminescence (Φlum). However, their dissymmetry factors (glum), differential left and right CPL intensities, are typically disappointingly low at least in one to two orders of magnitude. Truly useful organic CPL materials, rated by a circular polarization luminosity index (ΛCPL) per single molecule, possess both |glum| and Φlum values high. However, how to improve these two factors simultaneously with a proper molecular design is an open question. Here, we addressed this issue by theoretical and statistical inspection on a possible relation of the glum and Φlum values. According to the analysis, we propose simple, unpretentious, yet pertinent guidelines for designing superior organic CPL materials for the future with large ΛCPL values.

   @article{nagata2020irreverent,
     title = {Irreverent nature of dissymmetry factor and quantum yield in circularly polarized luminescence of small organic molecules},
     author = {Nagata, Yuya and Mori, Tadashi},
     journal = {Front. Chem.},
     volume = {8},
     pages = {448},
     year = {2020},
     publisher = {Frontiers Media SA},
     doi = {10.3389/fchem.2020.00448},
     url = {https://doi.org/10.3389/fchem.2020.00448},
     dimensions = {true},
     tab = {review},
   }

2019

1. 

   Sign control of circularly polarized luminescence based on geometric arrangement of fluorescent pyrene units in a binaphthyl scaffold

   Daiki Kaji, Shintaro Ikeda, Kenya Takamura, Nobuo Tajima, Motohiro Shizuma, Tadashi Mori, Makoto Miyasaka^*, and Yoshitane Imai^*

   Chem. Lett., 2019, 48, 874–876.

   Article Abs DOI Bib

   The signs of circularly polarized luminescence and circular dichroism of binaphthyl-pyrene fluorophores with the same axial chirality can be controlled by altering the bonding positions of the two fluorescent pyrene units in the solution state. The relative geometrical arrangement of the two pyrene rings plays a substantial role in determining the signs of the observed chiroptical properties.

   @article{kaji2019sign,
     title = {Sign control of circularly polarized luminescence based on geometric arrangement of fluorescent pyrene units in a binaphthyl scaffold},
     author = {Kaji, Daiki and Ikeda, Shintaro and Takamura, Kenya and Tajima, Nobuo and Shizuma, Motohiro and Mori, Tadashi and Miyasaka, Makoto and Imai, Yoshitane},
     journal = {Chem. Lett.},
     volume = {48},
     issue = {8},
     pages = {874--876},
     year = {2019},
     publisher = {Oxford University Press},
     doi = {10.1246/cl.190246},
     url = {https://doi.org/10.1246/cl.190246},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Diastereoselective Photocycloaddition Reaction of Vinyl Ether Tethered to 1, 4-Naphthoquinone

   Hiroki Ishikawa, Tim S Chung, Gaku Fukuhara, Hajime Shigemitsu, Toshiyuki Kida, Thorsten Bach, and Tadashi Mori^*

   ChemPhotoChem, 2019, 3, 243–250.

   Article Abs DOI Bib

   The intramolecular asymmetric photocycloaddition between 1,4-naphthoquinone and vinyl ether with a small (R)-point-chiral group on the tether was studied. Under photoirradiation, [2+2] cyclobutane products were exclusively obtained for this intramolecular system. The effect of solvent polarity on the stereoselectivity was significant, with predominant formation of the (2R,S3) over the (2R,R3) isomer in non-polar solvents being reversed in slightly polar dichloromethane. The detailed temperature-dependent study revealed the dominant diastereo-differentiating processes, which were switched between the ground-state equilibrium, the relative rate of bond formation in the triplet manifold, as well as deactivation processes between the pro-(S3) and pro-(R3) precursors, depending on the temperature domain examined. The enthalpic contribution (ΔΔH≠) was always compensated by the entropic factor (ΔΔS≠), implying the importance of solvation on the diastereo-differentiation steps. The mechanism of photocycloaddition, especially for the face-selective processes, is thoroughly discussed, which is supported by quantum chemical calculations on the ground-state circular dichroism (CD) spectral behavior as well as on the diastereomeric transition states in the triplet excited state.

   @article{ishikawa2019diastereoselective,
     title = {Diastereoselective Photocycloaddition Reaction of Vinyl Ether Tethered to 1, 4-Naphthoquinone},
     author = {Ishikawa, Hiroki and Chung, Tim S and Fukuhara, Gaku and Shigemitsu, Hajime and Kida, Toshiyuki and Bach, Thorsten and Mori, Tadashi},
     journal = {ChemPhotoChem},
     volume = {3},
     issue = {5},
     pages = {243--250},
     year = {2019},
     publisher = {Wiley Online Library},
     doi = {10.1002/cptc.201900022},
     url = {https://doi.org/10.1002/cptc.201900022},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Transient circular dichroism measurement of the excited triplet state of pristine hexahelicene in solution at room temperature

   Makoto Kuronuma, Takehito Sato, Yasuyuki Araki^*, Tadashi Mori, Seiji Sakamoto, Yoshihisa Inoue, Osamu Ito, and Takehiko Wada^*

   Chem. Lett., 2019, 48, 357–360.

   Article Abs DOI Bib

   The intramolecular asymmetric photocycloaddition between 1,4-naphthoquinone and vinyl ether with a small (R)-point-chiral group on the tether was studied. Under photoirradiation, [2+2] cyclobutane products were exclusively obtained for this intramolecular system. The effect of solvent polarity on the stereoselectivity was significant, with predominant formation of the (2R,S3) over the (2R,R3) isomer in non-polar solvents being reversed in slightly polar dichloromethane. The detailed temperature-dependent study revealed the dominant diastereo-differentiating processes, which were switched between the ground-state equilibrium, the relative rate of bond formation in the triplet manifold, as well as deactivation processes between the pro-(S3) and pro-(R3) precursors, depending on the temperature domain examined. The enthalpic contribution (ΔΔH≠) was always compensated by the entropic factor (ΔΔS≠), implying the importance of solvation on the diastereo-differentiation steps. The mechanism of photocycloaddition, especially for the face-selective processes, is thoroughly discussed, which is supported by quantum chemical calculations on the ground-state circular dichroism (CD) spectral behavior as well as on the diastereomeric transition states in the triplet excited state.

   @article{kuronuma2019transient,
     title = {Transient circular dichroism measurement of the excited triplet state of pristine hexahelicene in solution at room temperature},
     author = {Kuronuma, Makoto and Sato, Takehito and Araki, Yasuyuki and Mori, Tadashi and Sakamoto, Seiji and Inoue, Yoshihisa and Ito, Osamu and Wada, Takehiko},
     journal = {Chem. Lett.},
     volume = {48},
     issue = {4},
     pages = {357--360},
     year = {2019},
     publisher = {Oxford University Press},
     doi = {10.1246/cl.190012},
     url = {https://doi.org/10.1246/cl.190012},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Hydrostatic pressure on toroidal interaction and propeller chirality of hexaarylbenzenes: explicit solvent effects on differential volumes in methylcyclohexane and hexane

   Tomoyo Kosaka, Satono Iwai, Gaku Fukuhara^*, Yoshitane Imai, and Tadashi Mori^*

   Chem. Eur. J., 2019, 25, 2011–2018.

   Article Abs DOI Bib

   A unique and effective interaction between the peripheral aromatic blades makes hexaarylbenzenes (HABs) attractive in fundamental research as well as for various applications such as molecular wires, sensors, and supramolecular assemblies. The chiroptical responses of HABs are susceptible to environmental factors such as solvent and temperature owing to the dynamic conformational transitions between the conformers. In this study, pressure dependence on the propeller chiral HABs in two different solvents was studied in detail. The effective differential volumes for two different equilibria were determined by quantitative analyses of CD spectra, affording very large differential volumes from the propeller to toroidal conformer (ΔVT-C) of +43 and +42 cm3 mol−1, for H2 and H6, respectively, in methylcyclohexane. The value of H6 was further enhanced to +72 cm3 mol−1 in hexane, the largest value for the typical unimolecular conformational change. Such a response of propeller chirality in HABs is expedient in designing more advanced piezo-sensitive materials.

   @article{kosaka2019hydrostatic,
     title = {Hydrostatic pressure on toroidal interaction and propeller chirality of hexaarylbenzenes: explicit solvent effects on differential volumes in methylcyclohexane and hexane},
     author = {Kosaka, Tomoyo and Iwai, Satono and Fukuhara, Gaku and Imai, Yoshitane and Mori, Tadashi},
     journal = {Chem. Eur. J.},
     volume = {25},
     issue = {8},
     pages = {2011--2018},
     year = {2019},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201804688},
     url = {https://doi.org/10.1002/chem.201804688},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Selective Formation of Helical Tetrapyrrin-Fused Porphyrins by Oxidation of β-to-β Linked meso-Aminoporphyrin Dimers

   Keisuke Fujimoto, Daiki Shimizu, Tadashi Mori, Yuanyuan Li, Mingbo Zhou, Jianxin Song, and Atsuhiro Osuka^*

   Chem. Eur. J., 2019, 25, 1711–1715.

   Article Abs DOI Bib

   Oxidation of β-to-β directly linked and sulfur-bridged meso-amino NiII-porphyrin dimers with PbO2 gave helical tetrapyrrin (biliverdin analogue)-fused NiII-porphyrins. These ring cleaving reactions differ markedly from the previously reported oxidation of a β–β linked NiII-porphyrin dimer carrying one amino group, which gave an azepine-fused porphyrin dimer. The tetrapyrrin-fused NiII-porphyrins display intense NIR absorption bands at 1200–1400 nm and reversible redox processes because of the highly π-conjugated networks and rigid structures. These tetrapyrrin-fused NiII-porphyrins were separated to stable enantiomers, which showed clear Cotton effects in their CD spectra with Δϵ of 102 order.

   @article{fujimoto2019selective,
     title = {Selective Formation of Helical Tetrapyrrin-Fused Porphyrins by Oxidation of β-to-β Linked meso-Aminoporphyrin Dimers},
     author = {Fujimoto, Keisuke and Shimizu, Daiki and Mori, Tadashi and Li, Yuanyuan and Zhou, Mingbo and Song, Jianxin and Osuka, Atsuhiro},
     journal = {Chem. Eur. J.},
     volume = {25},
     issue = {7},
     pages = {1711--1715},
     year = {2019},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201805659},
     url = {https://doi.org/10.1002/chem.201805659},
     dimensions = {true},
     tab = {paper},
   }

6. 

   An ultimate stereocontrol in supramolecular photochirogenesis: photocyclodimerization of 2-anthracenecarboxylate mediated by sulfur-linked β-cyclodextrin dimers

   Jiecheng Ji, Wanhua Wu, Wenting Liang, Guo Cheng, Ryohei Matsushita, Zhiqiang Yan, Xueqin Wei, Ming Rao, De-Qi Yuan, Gaku Fukuhara, Tadashi Mori, Yoshihisa Inoue^*, and Cheng Yang^*

   J. Am. Chem. Soc., 2019, 141, 9225–9238.

   Article Abs DOI Bib

   Stereoisomeric β-cyclodextrin (CD) dimers linked with a sulfur atom or an arene spacer were designed to create a tethered dual CD capsule for precisely manipulating the regio- and enantioselectivities of the photocyclodimerization of 2-anthracenecarboxylate (AC) to four stereoisomeric classical 9,10:9′,10′-cyclodimers and two nonclassical 5,8:9′,10′-cyclodimers. Among the dimeric CD hosts prepared, exo-3-thia-β-CD dimer formed 1:1 and 1:2 host–guest complexes with AC in aqueous solutions, the former of which hindered but the latter facilitated the AC photocyclodimerization with regio- and enantioselectivities much higher than those obtained with native β-CD or the rest of the β-CD dimers. The stereochemical outcomes turned out to be highly sensitive to and hence critically manipulable by the linking position and configuration of the connected saccharide units and the linker length, as well as the external variants, such as temperature, pH, and added salt. Eventually, the photocyclodimerization of AC mediated by the dimeric β-CD host gave enantiopure syn-head-to-tail-9,10:9′,10′-cyclodimer in 97–98% yield in a pH 5.1 buffer solution at 0.5 °C and also in an aqueous CsCl solution at −20 °C.

   @article{ji2019ultimate,
     title = {An ultimate stereocontrol in supramolecular photochirogenesis: photocyclodimerization of 2-anthracenecarboxylate mediated by sulfur-linked β-cyclodextrin dimers},
     author = {Ji, Jiecheng and Wu, Wanhua and Liang, Wenting and Cheng, Guo and Matsushita, Ryohei and Yan, Zhiqiang and Wei, Xueqin and Rao, Ming and Yuan, De-Qi and Fukuhara, Gaku and Mori, Tadashi and Inoue, Yoshihisa and Yang, Cheng},
     journal = {J. Am. Chem. Soc.},
     volume = {141},
     number = {23},
     pages = {9225--9238},
     year = {2019},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.9b01993},
     url = {https://doi.org/10.1021/jacs.9b01993},
     dimensions = {true},
     tab = {paper},
   }

2018

1. 

   Spiroborate-based double-stranded helicates: meso-to-racemo isomerization and ion-triggered springlike motion of the racemo-helicate

   Naoki Ousaka, Kaori Shimizu, Yoshimasa Suzuki, Takuya Iwata, Manabu Itakura, Daisuke Taura, Hiroki Iida, Yoshio Furusho, Tadashi Mori, and Eiji Yashima^*

   J. Am. Chem. Soc., 2018, 140, 17027–17039.

   Article Abs DOI Bib

   A one-handed double-stranded spiroborate helicate exhibits a unique reversible extension–contraction motion coupled with a twisting motion in one direction triggered by binding and release of a Na+ ion while retaining its handedness. Here we report that an extended meso-helicate was also produced together with the racemo-helicate, and the meso-helicate was readily converted to the racemo-helicate assisted by a Na+ ion as a template in the presence of water. The thermodynamic analyses of the ion-triggered springlike motion of the racemo-helicate using a series of monovalent cations with different sizes revealed that the association constants of the extended racemo-helicate decreased in the following order: Li+ > Na+ > NH4+ > Ag+ ≥ K+ > Cs+ > Rb+, which roughly agrees with the reverse order of their ionic radii except for the NH4+ ion due to the more elongated contracted helicates when complexed with larger cations as supported by the crystal and DFT calculated structures. The one-handed contracted helicates showed characteristic CD spectra depending on the cation species due to the differences in their contracted helical structures, and its absolute handedness of the spiroborate helicate was determined by X-ray crystallography. The kinetic studies of the springlike motions of the racemo-helicate showed that the exchange rate between the extended and contracted helicates tend to increase in the following order: Li+ < Na+ < K+ ≤ NH4+ < Rb+ < Cs+ < Ag+ as anticipated from the association constants, being in good agreement with the order of the cation sizes except for Ag+.

   @article{ousaka2018spiroborate,
     title = {Spiroborate-based double-stranded helicates: meso-to-racemo isomerization and ion-triggered springlike motion of the racemo-helicate},
     author = {Ousaka, Naoki and Shimizu, Kaori and Suzuki, Yoshimasa and Iwata, Takuya and Itakura, Manabu and Taura, Daisuke and Iida, Hiroki and Furusho, Yoshio and Mori, Tadashi and Yashima, Eiji},
     journal = {J. Am. Chem. Soc.},
     volume = {140},
     issue = {49},
     pages = {17027--17039},
     year = {2018},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.8b08268},
     url = {https://doi.org/10.1021/jacs.8b08268},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Symmetry-based rational design for boosting chiroptical responses

   Hiroki Tanaka, Mina Ikenosako, Yuka Kato, Michiya Fujiki, Yoshihisa Inoue, and Tadashi Mori^*

   Communications Chemistry, 2018, 1, 38.

   Article Abs DOI Bib

   Chiral molecules play indispensable roles in advanced materials and technologies. Nevertheless, no conventional, yet reliable logical strategies are available for designing chiral molecules of desired chiroptical properties. Here, we propose a general protocol for rationally aligning multiple chiral units to boost the chiroptical responses, using hexahelicene as a prototype. In this proof-of-concept study, we align two hexahelicenes in various orientations and examine by theoretical calculations to predict the best chiroptical performance for X-shaped and S-shaped double hexahelicenes. We synthesize and optically resolve both double hexahelicenes and show that they exhibit more than a twofold increase in intensity of circular dichroism and circularly polarized luminescence, experimentally validating the protocol. The enhanced chiroptical responses are theoretically assignable to the electric and magnetic transition dipole moments of component hexahelicenes aligned in the correct symmetry. A guiding principle for designing advanced molecular and supramolecular chiral materials is further discussed.

   @article{tanaka2018symmetry,
     title = {Symmetry-based rational design for boosting chiroptical responses},
     author = {Tanaka, Hiroki and Ikenosako, Mina and Kato, Yuka and Fujiki, Michiya and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {Communications Chemistry},
     volume = {1},
     issue = {1},
     pages = {38},
     year = {2018},
     publisher = {Nature Publishing Group UK London},
     doi = {10.1038/s42004-018-0035-x},
     url = {https://doi.org/10.1038/s42004-018-0035-x},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Significant Enhancement of Absorption and Luminescence Dissymmetry Factors in the Far-Red Region: A Zinc (II) Homoleptic Helicate Formed by a Pair of Achiral Dipyrromethene Ligands

   Hiroaki Ito, Hayato Sakai, Yoshinori Okayasu, Junpei Yuasa, Tadashi Mori^*, and Taku Hasobe^*

   Chem. Eur. J., 2018, 24, 16889–16894.

   Article Abs DOI Bib

   A homoleptic zinc(II) helicate organized by a pair of achiral dipyrromethene ligands through zinc(II) coordination was synthesized to evaluate the chiroptical properties. This zinc complex showed strong exciton-coupled chiroptical responses from the helical configuration with a large absorption dissymmetry factor |gabs| (up to 0.20). More importantly, intense polarized luminescence in the far-red region (700–850 nm) with a fluorescence quantum yield ΦFL of 0.23 was observed for this helicate with a dissymmetry factor |glum| of 0.022, the largest value among rare-earth- and precious-metal-free small molecules. These unprecedentedly large g values were supported by theoretical calculations.

   @article{ito2018significant,
     title = {Significant Enhancement of Absorption and Luminescence Dissymmetry Factors in the Far-Red Region: A Zinc (II) Homoleptic Helicate Formed by a Pair of Achiral Dipyrromethene Ligands},
     author = {Ito, Hiroaki and Sakai, Hayato and Okayasu, Yoshinori and Yuasa, Junpei and Mori, Tadashi and Hasobe, Taku},
     journal = {Chem. Eur. J.},
     volume = {24},
     issue = {63},
     pages = {16889--16894},
     year = {2018},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201804171},
     url = {https://doi.org/10.1002/chem.201804171},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Combined Experimental and Theoretical Study on Circular Dichroism and Circularly Polarized Luminescence of Configurationally Robust D3-Symmetric Triple Pentahelicene

   Hiroki Tanaka, Yuka Kato, Yoshihisa Inoue, and Tadashi Mori^*

   J. Phys. Chem. A, 2018, 122, 7378–7384.

   Article Abs DOI Bib

   Pentahelicene (PH) exhibits the largest absorption (gabs) and luminescence (glum) dissymmetry factors among the helicene family but is configurationally and (photo)chemically labile, encumbering its application to chiroptical materials. To bypass the pitfalls, three PH units are merged in a single molecule to build D3-symmetric triple pentahelicene, hexabenzotriphenylene (HBT), which attains indeed the configurational and (photo)chemical robustness through equilibrium with a C2-symmetric conformer that interrupts the racemization and photocyclization. UV–vis, circular dichroism (CD), and circularly polarized luminescence (CPL) spectral examinations reveal the significantly larger gabs and glum values for HBT than for any of configurationally robust single [n]helicene (n ≥ 6) and C2-symmetric triple pentahelicene, trinaphthotriphenylene (TNT). Theoretical calculations precisely reproduce the main features of the experimental CD and CPL spectra of PH, HBT, and TNT, and the relevant electric and magnetic transition moments and their mutual angles well rationalize the relative CD and CPL intensities of all the single and triple pentahelicenes.

   @article{tanaka2018combined,
     title = {Combined Experimental and Theoretical Study on Circular Dichroism and Circularly Polarized Luminescence of Configurationally Robust D3-Symmetric Triple Pentahelicene},
     author = {Tanaka, Hiroki and Kato, Yuka and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {J. Phys. Chem. A},
     volume = {122},
     issue = {37},
     pages = {7378--7384},
     year = {2018},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.8b05247},
     url = {https://doi.org/10.1021/acs.jpca.8b05247},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Solvent and temperature effects on dynamics and chiroptical properties of propeller chirality and toroidal interaction of hexaarylbenzenes

   Tomoyo Kosaka, Satono Iwai, Yoshihisa Inoue, Toshiyuki Moriuchi, and Tadashi Mori^*

   The Journal of Physical Chemistry A, 2018, 122, 7455–7463.

   Article Abs DOI Bib

   Because of the unique interaction of radial aromatic blades, propeller-shaped hexaarylbenzenes (HABs) attract much research interest and find various practical applications. By introducing a small point-chiral group at the tip of aromatic blade(s), HAB becomes propeller-chiral to exhibit strong Cotton effects. Because of the dynamic nature of propeller chirality, the chiroptical properties of HAB critically responded to minute changes in the environment. Using a series of chiral HABs with one to six (R)-1-methylpropyloxy substituent(s) introduced at the blade tip, we elucidated how the smallest chiral auxiliary at the HAB periphery progressively and cooperatively boosts the overall chiroptical properties and also how subtle changes in temperature and solvent structure affect the propeller dynamics and thus the chiroptical responses. The unique features of propeller-chiral HABs further enabled us to switch on/off their circularly polarized luminescence.

   @article{kosaka2018solvent,
     title = {Solvent and temperature effects on dynamics and chiroptical properties of propeller chirality and toroidal interaction of hexaarylbenzenes},
     author = {Kosaka, Tomoyo and Iwai, Satono and Inoue, Yoshihisa and Moriuchi, Toshiyuki and Mori, Tadashi},
     journal = {The Journal of Physical Chemistry A},
     volume = {122},
     issue = {37},
     pages = {7455--7463},
     year = {2018},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.8b06535},
     url = {https://doi.org/10.1021/acs.jpca.8b06535},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Synthesis, structures, and optical properties of azahelicene derivatives and unexpected formation of azahepta [8] circulenes

   Fengkun Chen, Takayuki Tanaka^*, Tadashi Mori, and Atsuhiro Osuka^*

   Chem. Eur. J., 2018, 24, 7489–7497.

   Article Abs DOI Bib

   Polycyclic heteroaromatic compounds including pyrrole units are promising functional scaffolds owing to their electron-rich nature, bright fluorescence, and applicability to anion recognition at the pyrrolic hydrogen atom. We report herein the effective synthesis of pseudo-aza[5]helicene and aza[7]helicene derivatives, and unexpected formation of azahepta[8]circulenes by oxidative fusion reactions. By choosing reaction conditions and peripheral substituents attached at the terminal indole moieties, we obtained aza[7]helicenes 10 a–c and azahepta[8]circulenes 11 a,c selectively in moderate to good yields. Their solid-state structures have been revealed by X-ray diffraction analysis. UV/Vis absorption, emission, and cyclic voltammetry of these compounds were studied in comparison with those of previously reported tetraaza[8]circulene (TA8C), a symmetric and planar molecule. Furthermore, the enantiomeric separation of dimethyl-substituted aza[7]helicene 10 b was achieved, and the racemization kinetics have been elucidated both theoretically and experimentally. This work illustrates a wealth of advantages of pyrrole incorporation into the polycyclic aromatic scaffolds in terms of synthetic aspects, structural variation, and optical tuning.

   @article{chen2018synthesis,
     title = {Synthesis, structures, and optical properties of azahelicene derivatives and unexpected formation of azahepta [8] circulenes},
     author = {Chen, Fengkun and Tanaka, Takayuki and Mori, Tadashi and Osuka, Atsuhiro},
     journal = {Chem. Eur. J.},
     volume = {24},
     issue = {29},
     pages = {7489--7497},
     year = {2018},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201800617},
     url = {https://doi.org/10.1002/chem.201800617},
     dimensions = {true},
     tab = {paper},
   }

7. 

   1, 8-Diphenyl-9, 10-Bis (arylethynyl) phenanthrenes: Synthesis, Distorted Structure, and Optical Properties

   Akihito Konishi^*, Atsushi Morinaga, Gaku Fukuhara, Masaki Nishijima, Tadashi Mori, Toshiyuki Kida, and Makoto Yasuda^*

   Chem. Eur. J., 2018, 24, 6625–6631.

   Article Abs DOI Bib

   The synthesis and optical properties of 1,8-diphenyl-9,10-bis(arylethynyl)phenanthrenes, which are distorted phenanthrenes, are reported. The presence of the two phenyl groups at the 1,8-positions of phenanthrene significantly distorts the molecular geometries, as was evidenced by X-ray crystallography. The congested substitution pattern in the K region results in a distorted aromatic framework, which leads to a redshift in the emission spectrum. These observations are in stark contrast to 9,10-bis(phenylethynyl)phenanthrene with no phenyl groups at the 1,8-positions. A large Stokes shift suggested extensive structural relaxation between the phenyl and arylethynyl units in the excited state, which was supported by theoretical calculations.

   @article{konishi20181,
     title = {1, 8-Diphenyl-9, 10-Bis (arylethynyl) phenanthrenes: Synthesis, Distorted Structure, and Optical Properties},
     author = {Konishi, Akihito and Morinaga, Atsushi and Fukuhara, Gaku and Nishijima, Masaki and Mori, Tadashi and Kida, Toshiyuki and Yasuda, Makoto},
     journal = {Chem. Eur. J.},
     volume = {24},
     issue = {25},
     pages = {6625--6631},
     year = {2018},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201800617},
     url = {https://doi.org/10.1002/chem.201800617},
     dimensions = {true},
     tab = {paper},
   }

8. 

   Circularly polarized luminescence and circular dichroisms in small organic molecules: correlation between excitation and emission dissymmetry factors

   Hiroki Tanaka, Yoshihisa Inoue, and Tadashi Mori^*

   ChemPhotoChem, 2018, 2, 386–402.

   Review Abs DOI Bib

   Prompted by the recent rapid growth of interest in circularly polarized luminescence (CPL) of organic molecules, we have collected all the reliable CPL, as well as the corresponding circular dichroism (CD), data measured in fluid solutions. To analyze the correlation between CPL and CD, we employed the absorption and luminescence dissymmetry factors (gabs and glum) of the π–π* transition reported for chiral organic molecules of various categories, including planar chiral cyclophanes and helicenes, axially chiral biaryls and spiro compounds, and point- and axially chiral BODIPY derivatives. In rigid π-systems, the absorption and fluorescence spectra are often mirror images of each other with a small Stokes shift, reflecting the minimal conformational relaxation in the emissive excited state, which should also affect the chiroptical properties in the excited state and be better sensed by CPL. However, no comprehensive efforts have hitherto been made to correlate the two relevant chiroptical properties, i.e. CPL versus CD, and also to quantitatively elucidate the effects of conformational relaxation in the excited state on the CPL behavior. The global linear regression analysis of all the reported gabs and glum values, though fairly scattered (see TOC), led us to a quantitative relationship: |glum|=0.81×|gabs| (r2=0.60), which demonstrates that the CPL dissymmetry factor is proportional to, and smaller than, the CD dissymmetry factor. A closer look revealed that the slope of the plot, or the proportional coefficient, is a critical function of the class of compounds, varying from 0.99 for cyclophanes to 0.93 for biaryls, to 0.77 for BODIPYs, and then to 0.61 for helicenes/helicenoids. The scattered glum–gabs plot and the general trend glum≤gabs appear to be inherent to the CPL of organic molecules in their isolated states, originating from the conformational flexibility, vibrational contribution, and Stokes shift that differ in each category.

   @article{tanaka2018circularly,
     title = {Circularly polarized luminescence and circular dichroisms in small organic molecules: correlation between excitation and emission dissymmetry factors},
     author = {Tanaka, Hiroki and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {ChemPhotoChem},
     volume = {2},
     issue = {5},
     pages = {386--402},
     year = {2018},
     publisher = {Wiley Online Library},
     doi = {10.1002/cptc.201800015},
     url = {https://doi.org/10.1002/cptc.201800015},
     dimensions = {true},
     tab = {review},
   }

9. 

   Entropy-Driven Diastereoselectivity Improvement in the Paternò–Büchi Reaction of 1-Naphthyl Aryl Ethenes with a Chiral Cyanobenzoate through Remote Alkylation

   Keisuke Nagasaki, Yoshihisa Inoue, and Tadashi Mori^*

   Angew. Chem. Int. Ed., 2018, 57, 4880–4885.

   Article Abs DOI Bib

   The precise stereocontrol of photocycloaddition reactions is still a significant challenge owing to their mechanistic complexity and the involvement of highly reactive and short-lived intermediates. Attempts have hitherto been made through structural modifications, mostly by introducing steric conflicts, to increase the difference between the enthalpic barriers. Herein, we show that entropy plays a crucial role in influencing the diastereoselectivity of a Paternò–Büchi reaction. Remote meta alkylation of the donor caused nominal changes in its photophysical properties as well as those of the exciplexes derived thereof. Nevertheless, the diastereomeric excess of the oxetane product was greatly improved by about 40%. This enhancement, which is not accompanied by any significant changes in the photophysical properties, is difficult to rationalize by conventional enthalpic control concepts based on repulsive steric and/or attractive intermolecular interactions as well as electronic perturbations. Differential activation parameters and compensatory enthalpy–entropy relationships revealed that the diastereoselectivity enhancement is not simply enthalpic but also entropic in origin.

   @article{nagasaki2018entropy,
     title = {Entropy-Driven Diastereoselectivity Improvement in the Paternò--Büchi Reaction of 1-Naphthyl Aryl Ethenes with a Chiral Cyanobenzoate through Remote Alkylation},
     author = {Nagasaki, Keisuke and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {Angew. Chem. Int. Ed.},
     volume = {57},
     issue = {18},
     pages = {4880--4885},
     year = {2018},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.201801330},
     url = {https://doi.org/10.1002/anie.201801330},
     dimensions = {true},
     tab = {paper},
   }

10. 

    Supramolecular photochirogenesis driven by higher-order complexation: enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate to slipped cyclodimers via a 2: 2 complex with β-cyclodextrin

    Xueqin Wei, Wanhua Wu, Ryohei Matsushita, Zhiqiang Yan, Dayang Zhou, Jason J Chruma, Masaki Nishijima, Gaku Fukuhara, Tadashi Mori, Yoshihisa Inoue^*, and Cheng Yang^*

    J. Am. Chem. Soc., 2018, 140, 3959–3974.

    Article Abs DOI Bib

    Chiral slipped 5,8:9′,10′-cyclodimers were preferentially produced over classical 9,10:9′,10′-cyclodimers upon supramolecular photocyclodimerization of 2-anthracenecarboxylate (AC) mediated by β-cyclodextrin (β-CD). This photochirogenic route to the slipped cyclodimers, exclusively head-to-tail (HT) and highly enantioselective, has long been overlooked in foregoing studies but is dominant in reality and is absolutely supramolecularly activated by 2:2 complexation of AC with β-CD. The intricate structural and photophysical aspects of this higher-order complexation-triggered process have been comprehensively elucidated, while the absolute configurations of the slipped cyclodimers have been unambiguously assigned by comparing the experimental and theoretical circular dichroism spectra. In the 2:2 complex, two ACs packed in a dual β-CD capsule are not fully overlapped with each other but are only partially stacked in a slipped anti- or syn-HT manner. Hence, they do not spontaneously cyclodimerize upon photoexcitation but instead emit long-lived excimer fluorescence at wavelengths slightly longer than the monomer fluorescence, indicating that the slipped excimer is neither extremely reactive nor completely relaxed in conformation and energy. Because of the slipped conformation of the AC pair in the soft capsule, the subsequent photocyclodimerization becomes manipulable by various internal or external factors, such as temperature, pressure, added salt, and host modification, enabling us to exclusively obtain the slipped cyclodimers with high regio- and enantioselectivities. In this supramolecularly driven photochirogenesis, the dual β-CD capsule functions as a chiral organophotocatalyst to trigger and accelerate the nonclassical photochirogenic route to slipped cyclodimers by preorganizing the conformation of the encapsulated AC pair, formally mimicking a catalytic antibody.

    @article{wei2018supramolecular,
      title = {Supramolecular photochirogenesis driven by higher-order complexation: enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate to slipped cyclodimers via a 2: 2 complex with β-cyclodextrin},
      author = {Wei, Xueqin and Wu, Wanhua and Matsushita, Ryohei and Yan, Zhiqiang and Zhou, Dayang and Chruma, Jason J and Nishijima, Masaki and Fukuhara, Gaku and Mori, Tadashi and Inoue, Yoshihisa and Yang, Cheng},
      journal = {J. Am. Chem. Soc.},
      volume = {140},
      issue = {11},
      pages = {3959--3974},
      year = {2018},
      publisher = {ACS Publications},
      doi = {10.1021/jacs.7b12085},
      url = {https://doi.org/10.1021/jacs.7b12085},
      dimensions = {true},
      tab = {paper},
    }

11. 

    A BODIPY-based near infrared fluorescent probe for Fe3+ in water

    Jiecheng Ji, Syama Sundar Chereddy, Yi Ren, Xingming Chen, Dan Su, Zhihui Zhong, Tadashi Mori, Yoshihisa Inoue^*, Wanhua Wu, and Cheng Yang^*

    J. Photochem. Photobiol. A: Chem., 2018, 355, 78–83.

    Article Abs DOI Bib

    For highly sensitive and selective detection of biologically important Fe3+ in aqueous media, a novel near-infrared (NIR) fluorescent probe (λem = 627 nm; ΦF = 0.47) based on boron-dipyrromethene (BODIPY) was developed. Employing a pair of 2-sulfonatostyryl sidearms attached to the BODIPY core as a reversible chelator specific to Fe3+, the sensor achieved a high selectivity toward Fe3+ over a wide range of metal ions, including Li+, Na+, K+, Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Al3+, and Cr3+. Furthermore, the quenched NIR fluorescence was immediately recovered upon addition of sodium ascorbate as a reductant or EDTA as a stronger chelator.

    @article{ji2018bodipy,
      title = {A BODIPY-based near infrared fluorescent probe for Fe3+ in water},
      author = {Ji, Jiecheng and Chereddy, Syama Sundar and Ren, Yi and Chen, Xingming and Su, Dan and Zhong, Zhihui and Mori, Tadashi and Inoue, Yoshihisa and Wu, Wanhua and Yang, Cheng},
      journal = {J. Photochem. Photobiol. A: Chem.},
      volume = {355},
      pages = {78--83},
      year = {2018},
      publisher = {Elsevier},
      doi = {10.1016/j.jphotochem.2017.10.043},
      url = {https://doi.org/10.1016/j.jphotochem.2017.10.043},
      dimensions = {true},
      tab = {paper},
    }

12. 

    Circular Dichroisms of Mono-and Dibromo [2.2] paracyclophanes: A Combined Experimental and Theoretical Study

    Mitsunobu Toda, Yoshihisa Inoue, and Tadashi Mori^*

    ACS Omega, 2018, 3, 22–29.

    Article Abs DOI Bib

    Circular dichroisms (CDs) of planar chiral 4-bromo[2.2]paracyclophane (1) and three isomeric dibromo[2.2]paracyclophanes (p-2, m′-2, and o′-2) were investigated experimentally and theoretically. They all exhibited strong multisignate Cotton effects (CEs) at the 1Lb, 1La, and 1B transitions of the component (bromo)benzene chromophore and were comparable to each other. For all of the cyclophanes examined, the enantiomer that eluted earlier from a chiral high-performance liquid chromatography column (Chiralcel IA or IB) exhibited negative and positive CEs at the 1Lb and 1La bands, respectively, which were followed by a more complicated pattern of CDs at the higher-energy bands. These CD features were well reproduced by quantum chemical calculations, allowing us to unambiguously assign the absolute configurations of the first-eluted enantiomers as Rp in all of the cases examined. Interestingly, the CDs of 1 and 2, although largely comparable in shape, were still sensitive to the number and pattern of bromine substitution, showing closer resemblance between m-2 and o-2 and between p-2 and 1. The theoretical calculations also reproduced successfully these spectral resemblance between them. The anisotropy (g) factors for the 1Lb bands of these cyclophanes were considerably large (∼10–2), whereas those for the 1La band were conventional in the order of 10–3. In addition, a weak CE was observed in the low-energy region at around 320 nm, which turned out to originate from the interplanar interaction and is hence assigned to the “cyclophane band”. The experimental g factors of this band were fairly large in the order of 10–2, but the computation turned out to be quite challenging and were less well reproduced theoretically, ascribable to the forbidden nature of the transition.

    @article{toda2018circular,
      title = {Circular Dichroisms of Mono-and Dibromo [2.2] paracyclophanes: A Combined Experimental and Theoretical Study},
      author = {Toda, Mitsunobu and Inoue, Yoshihisa and Mori, Tadashi},
      journal = {ACS Omega},
      volume = {3},
      issue = {1},
      pages = {22--29},
      year = {2018},
      publisher = {ACS Publications},
      doi = {10.1021/acsomega.7b01642},
      url = {https://doi.org/10.1021/acsomega.7b01642},
      dimensions = {true},
      tab = {paper},
    }

13. 

    Porphyrin-Based Air-Stable Helical Radicals

    Kenichi Kato, Ko Furukawa^*, Tadashi Mori, and Atsuhiro Osuka^*

    Chem. Eur. J., 2018, 24, 572–575.

    Article Abs DOI Bib

    Stable helical radicals are promising multi-functional molecules in light of intriguing magnetic and chiroptical properties. Attempts were made to extend diphenylmethyl-fused NiII porphyrin radical to helical system as the first air-stable organic neutral helical radicals. Intramolecular Pd-catalyzed twofold C−H arylation of methyl- or methoxy-introduced meso-diphenylmethyl NiII porphyrins gave a mixture of the target and rearranged radicals. Oxidative fusion reaction of meso-(bis(1-naphthyl)methyl) NiII porphyrins provided doubly fused NiII porphyrin radicals. One of the helical radicals was separated into enantiomers that showed mirror-image circular dichroism (CD) spectra up to 1300 nm. The helical dinaphthylmethyl-fused NiII porphyrin radical displayed solid-state magnetic property mostly arising from monomeric radicals, different from the parent diphenylmethyl-fused NiII porphyrin radical that showed antiferromagnetic coupling due to π-stacked pairing.

    @article{kato2018porphyrin,
      title = {Porphyrin-Based Air-Stable Helical Radicals},
      author = {Kato, Kenichi and Furukawa, Ko and Mori, Tadashi and Osuka, Atsuhiro},
      journal = {Chem. Eur. J.},
      volume = {24},
      number = {3},
      pages = {572--575},
      year = {2018},
      publisher = {Wiley Online Library},
      doi = {10.1002/chem.201705291},
      url = {https://doi.org/10.1002/chem.201705291},
      dimensions = {true},
      tab = {paper},
    }

14. 

    Preface for special issue on photosynergetics

    Vasudevanpillai Biju^*, Tadashi Mori^*, Tsuyoshi Asahi^*, and Hiroshi Miyasaka^*

    J. Photochem. Photobiol. C: Photochem. Rev., 2018, 34, 1.

    Article Abs DOI Bib

    Molecules in the electronic excited state photo-energy conversion natural artificial photosynthesis so forth. For molecules in condensed phase however three general restrictions limit the efficient utilization of light energy. First molecules in higher electronically-excited states rapidly relax to the lowest excited electronic state (Kasha’s rule) extinguishing some portion of the absorbed photon energy. Second a large number of molecules excited in assemblies undergo fast annihilation leaving only a small fraction in the excited state leading to the loss of a major fraction of the number of photons absorbed by the assemblies. Third the electronic state accessible through one-photon absorption is limited by the optical selection rule denying access to various dark electronic excited states of molecules.

    @article{biju2018preface,
      title = {Preface for special issue on photosynergetics},
      author = {Biju, Vasudevanpillai and Mori, Tadashi and Asahi, Tsuyoshi and Miyasaka, Hiroshi},
      journal = {J. Photochem. Photobiol. C: Photochem. Rev.},
      volume = {34},
      pages = {1},
      year = {2018},
      publisher = {Elsevier BV},
      doi = {10.1016/j.jphotochemrev.2018.02.003.},
      url = {https://doi.org/10.1016/j.jphotochemrev.2018.02.003.},
      dimensions = {true},
      tab = {paper},
    }

15. Propeller Chirality

    Tadashi Mori^*

    Kokagaku, 2018, 49, 163–166.

    Bib

    @article{mori2018propeller,
      title = {Propeller Chirality},
      author = {Mori, Tadashi},
      journal = {Kokagaku},
      volume = {49},
      issue = {3},
      pages = {163--166},
      year = {2018}
    }

2017

1. 

   Enantioselectivity of 2, 2′, 3, 5′, 6-pentachlorobiphenyl (PCB 95) atropisomers toward ryanodine receptors (RyRs) and their influences on hippocampal neuronal networks

   Wei Feng, Jing Zheng, Gaëlle Robin, Yao Dong, Makoto Ichikawa, Yoshihisa Inoue, Tadashi Mori, Takeshi Nakano, and Isaac N Pessah^*

   Environ. Sci. Technol., 2017, 51, 14406–14416.

   Article Abs DOI Bib

   Nineteen ortho-substituted PCBs are chiral and found enantioselectively enriched in ecosystems. Their differential actions on biological targets are not understood. PCB 95 (2,2′,3,5′,6-pentachlorobiphenyl), a chiral PCB of current environmental relevance, is among the most potent toward modifying ryanodine receptors (RyR) function and Ca2+ signaling. PCB 95 enantiomers are separated and assigned aR- and aS-PCB 95 using three chiral-column HPLC and circular dichroism spectroscopy. Studies of RyR1-enriched microsomes show aR-PCB 95 with >4× greater potency (EC50 = 0.20 ± 0.05 μM), ∼ 1.3× higher efficacy (Bmax = 3.74 ± 0.07 μM) in [3H]Ryanodine-binding and >3× greater rates (R = 7.72 ± 0.31 nmol/sec/mg) of Ca2+ efflux compared with aS-PCB 95, whereas racemate has intermediate activity. aR-PCB 95 has modest selectivity for RyR2, and lower potency than racemate toward the RyR isoform mixture in brain membranes. Chronic exposure of hippocampal neuronal networks to nanomolar PCB 95 during a critical developmental period shows divergent influences on synchronous Ca2+ oscillation (SCO): rac-PCB 95 increasing and aR-PCB 95 decreasing SCO frequency at 50 nM, although the latter’s effects are nonmonotonic at higher concentration. aS-PCB95 shows the greatest influence on inhibiting responses to 20 Hz electrical pulse trains. Considering persistence of PCB 95 in the environment, stereoselectivity toward RyRs and developing neuronal networks may clarify health risks associated with enantioisomeric enrichment of PCBs.

   @article{feng2017enantioselectivity,
     title = {Enantioselectivity of 2, 2′, 3, 5′, 6-pentachlorobiphenyl (PCB 95) atropisomers toward ryanodine receptors (RyRs) and their influences on hippocampal neuronal networks},
     author = {Feng, Wei and Zheng, Jing and Robin, Gaëlle and Dong, Yao and Ichikawa, Makoto and Inoue, Yoshihisa and Mori, Tadashi and Nakano, Takeshi and Pessah, Isaac N},
     journal = {Environ. Sci. Technol.},
     volume = {51},
     issue = {24},
     pages = {14406--14416},
     year = {2017},
     publisher = {ACS Publications},
     doi = {10.1021/acs.est.7b04446},
     url = {https://doi.org/10.1021/acs.est.7b04446},
     dimensions = {true},
     tab = {paper},
   }

2. 

   A combined experimental and theoretical study on the circular dichroism of staggered and eclipsed forms of dimethoxy [2.2]-,[3.2]-, and [3.3] pyridinophanes and their protonated forms

   Akinori Shimizu, Yoshihisa Inoue, and Tadashi Mori^*

   J. Phys. Chem. A, 2017, 121, 8389–8398.

   Article Abs DOI Bib

   The circular dichroisms (CDs) of dimethoxy[2.2]-, [3.2]-, and [3.3]pyridinophanes and their protonated forms were investigated experimentally and theoretically. Characteristic multisignate Cotton effects (CEs), typical for planar chiral cyclophane derivatives, were observed. The CD spectral pattern was quite comparable for the staggered forms of [2.2]-, [3.2]-, and [3.3]cyclophanes, but significantly differed for the eclipsed forms. More interestingly, the patterns resembled, but the CE signs were practically opposite between staggered and eclipsed [2.2]pyridinophanes. Upon protonation, the signs of most CEs were inverted in both forms of cyclophanes, due to the reversal of dipole moment in the pyridine against the pyridinium moiety. Such a change in CD spectrum upon protonation was not apparent in [3.2]pyridinophane, and the CD spectral behavior was more complex in [3.3]pyridinophanes. The variation of CD caused by the protonation/deprotonation process was temperature-dependent and hence utilized as a thermal sensor. The protonated forms of the homologous pyridinophanes with different tether lengths in staggered and eclipsed forms served as a model system for systematically studying the cation−π interaction and its effects on chiroptical properties. A steady increase of electronic interaction became apparent for the smaller-sized cyclophanes from the increased excitation energy and electronic coupling element of the charge-transfer (CT) band, while the observed CE at the CT band was a more complex function of the original transition dipole of donor/acceptor pair and linker atoms, as well as the strength of the electronic interaction.

   @article{shimizu2017combined,
     title = {A combined experimental and theoretical study on the circular dichroism of staggered and eclipsed forms of dimethoxy [2.2]-,[3.2]-, and [3.3] pyridinophanes and their protonated forms},
     author = {Shimizu, Akinori and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {J. Phys. Chem. A},
     volume = {121},
     issue = {44},
     pages = {8389--8398},
     year = {2017},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.7b08623},
     url = {https://doi.org/10.1021/acs.jpca.7b08623},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Chiroptical properties of dithia [3.3] cyclophanes composed of anthracene and pyridine/pyridinium moieties: A combined experimental and theoretical study

   Akinori Shimizu, Keisuke Nagasaki, Yoshihisa Inoue, and Tadashi Mori^*

   Chirality, 2017, 121, 8389–8398.

   Article Abs DOI Bib

   Circular dichroisms (CDs) of neutral and protonated [3.3]anthracenopyridinophane (1 and 1-H+) were investigated experimentally and theoretically. Introducing an anthracene moiety with extended conjugation affected the cyclophane structure with the bent angles being appreciably　reduced from those of parent [3.3]pyridinophane. The Cotton effects (CEs) observed at the 1Bb band for both 1 and 1-H+ were fairly strong and apparently bisignate, which, however, turned out not to be a simple exciton couplet but to be composed of multiple transitions. In contrast, the CEs were much weaker in the 1La band region. The spectral changes upon protonation were less significant compared with the parent pyridinophane, being dominated by the local transitions of anthracene. Nevertheless, the CD spectra of 1 and 1-H+ were well reproduced by theoretical calculations to allow us an unambiguous absolute configuration determination of the first high-performance liquid chromatography (HPLC) elute (from Chiralcel IB column) as Sp. The transannular interactions between the anthracene and pyridine/pyridinium units were examined by UV-vis and fluorescence spectroscopy to reveal a charge-transfer (CT) band in the low-energy region, particularly for 1-H+. Despite the comparable CT interactions, the CE at the CT band was much stronger for the anthracenopyridinophane than for the parent pyridinophane, affording an anisotropy (g) factor as large as 4 × 10-3.

   @article{shimizu2017chiroptical,
     title = {Chiroptical properties of dithia [3.3] cyclophanes composed of anthracene and pyridine/pyridinium moieties: A combined experimental and theoretical study},
     author = {Shimizu, Akinori and Nagasaki, Keisuke and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {Chirality},
     volume = {121},
     issue = {44},
     pages = {8389--8398},
     year = {2017},
     publisher = {ACS Publications},
     doi = {10.1002/chir.22740},
     url = {https://doi.org/10.1002/chir.22740},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Closed Pentaaza [9] helicene and Hexathia [9]/[5] helicene: Oxidative Fusion Reactions of ortho-Phenylene-Bridged Cyclic Hexapyrroles and Hexathiophenes

   Fengkun Chen, Takayuki Tanaka^*, Yong Seok Hong, Tadashi Mori, Dongho Kim^*, and Atsuhiro Osuka^*

   Angew. Chem. Int. Ed., 2017, 129, 14880–14885.

   Article Abs DOI Bib

   Oxidative fusion reactions of ortho-phenylene-bridged cyclic hexapyrroles and hexathiophenes furnished novel closed helicenes in a selective manner. X-Ray diffraction analysis unambiguously revealed the structures to be a closed pentaaza[9]helicene, the longest azahelicene reported so far, and an unexpected double-helical structure of hexathia[9]/[5]helicene, whose formation was assumed to result from multiple oxidative fusion along with a 1,2-aryl shift. The pentaaza[9]helicene exhibited well-defined emission with high fluorescence quantum yield (ΦF=0.31) among the known [9]helicenes. Chiral resolution of the racemic pentaaza[9]helicene and hexathia[9]/[5]helicene were achieved by chiral-phase HPLC and the enantiomers were characterized by circular dichroism spectra and DFT calculations.

   @article{chen2017closed,
     title = {Closed Pentaaza [9] helicene and Hexathia [9]/[5] helicene: Oxidative Fusion Reactions of ortho-Phenylene-Bridged Cyclic Hexapyrroles and Hexathiophenes},
     author = {Chen, Fengkun and Tanaka, Takayuki and Hong, Yong Seok and Mori, Tadashi and Kim, Dongho and Osuka, Atsuhiro},
     journal = {Angew. Chem. Int. Ed.},
     volume = {129},
     issue = {46},
     pages = {14880--14885},
     year = {2017},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.201708429},
     url = {https://doi.org/10.1002/anie.201708429},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Intense redox-driven chiroptical switching with a 580 mV hysteresis actuated through reversible dimerization of an azoniahelicene

   Jochen R Brandt, Lubomír Pospíšil, Lucie Bednárová, Rosenildo Correa Costa, Andrew JP White, Tadashi Mori, Filip Teplý, and Matthew J Fuchter^*

   Chem. Commun., 2017, 53, 9059–9062.

   Article Abs DOI Bib

   Electrochemical reduction of an azoniahelicene affords a dimer, accompanied by a strong change in the electronic circular dichroism. The fast dimerisation event leads to a >500 mV shift of the oxidation potential, affording a large area of bistability, where the chiroptical signal only depends on the redox history.

   @article{brandt2017intense,
     title = {Intense redox-driven chiroptical switching with a 580 mV hysteresis actuated through reversible dimerization of an azoniahelicene},
     author = {Brandt, Jochen R and Pospíšil, Lubomír and Bednárová, Lucie and da Costa, Rosenildo Correa and White, Andrew JP and Mori, Tadashi and Teplý, Filip and Fuchter, Matthew J},
     journal = {Chem. Commun.},
     volume = {53},
     issue = {65},
     pages = {9059--9062},
     year = {2017},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/c7cc04903j},
     url = {https://doi.org/10.1039/c7cc04903j},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Energetics of Baird aromaticity supported by inversion of photoexcited chiral [4n] annulene derivatives

   Michihisa Ueda, Kjell Jorner, Young Mo Sung, Tadashi Mori, Qi Xiao, Dongho Kim, Henrik Ottosson, Takuzo Aida, and Yoshimitsu Itoh^*

   Nat. Commun., 2017, 8, 346.

   Article Abs DOI Bib

   For the concept of aromaticity, energetic quantification is crucial. However, this has been elusive for excited-state (Baird) aromaticity. Here we report our serendipitous discovery of two nonplanar thiophene-fused chiral [4n]annulenes Th4 COT Saddle and Th6 CDH Screw , which by computational analysis turned out to be a pair of molecules suitable for energetic quantification of Baird aromaticity. Their enantiomers were separable chromatographically but racemized thermally, enabling investigation of the ring inversion kinetics. In contrast to Th6 CDH Screw , which inverts through a nonplanar transition state, the inversion of Th4 COT Saddle , progressing through a planar transition state, was remarkably accelerated upon photoexcitation. As predicted by Baird’s theory, the planar conformation of Th4 COT Saddle is stabilized in the photoexcited state, thereby enabling lower activation enthalpy than that in the ground state. The lowering of the activation enthalpy, i.e., the energetic impact of excited-state aromaticity, was quantified experimentally to be as high as 21–22 kcal mol–1.

   @article{ueda2017energetics,
     title = {Energetics of Baird aromaticity supported by inversion of photoexcited chiral [4n] annulene derivatives},
     author = {Ueda, Michihisa and Jorner, Kjell and Sung, Young Mo and Mori, Tadashi and Xiao, Qi and Kim, Dongho and Ottosson, Henrik and Aida, Takuzo and Itoh, Yoshimitsu},
     journal = {Nat. Commun.},
     volume = {8},
     issue = {1},
     pages = {346},
     year = {2017},
     publisher = {Nature Publishing Group UK London},
     doi = {10.1038/s41467-017-00382-1},
     url = {https://doi.org/10.1038/s41467-017-00382-1},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Oligosaccharide Sensing in Aqueous Media by Porphyrin–Curdlan Conjugates: A Prêt-á-Porter Rather Than Haute-Couture Approach

   Gaku Fukuhara^*, Mayuko Sasaki, Munenori Numata, Tadashi Mori, and Yoshihisa Inoue^*

   Chem. Eur. J., 2017, 23, 11272–11278.

   Article Abs DOI Bib

   Saccharide sensing in aqueous media is an intriguing but challenging goal in current chemistry. Herein we report the oligosaccharide-sensing behavior of newly synthesized porphyrin–curdlan conjugates, which are random coils in DMSO but become globules in aqueous solutions to induce circular dichroism (ICD) in the biologically accessible spectral region due to the conformational fixation of porphyrin reporters. The magnitude of ICD was significantly varied specifically in the presence of acarbose, a drug for type-2 diabetes, enabling us to detect the aminosaccharide at concentrations down to 200 μm. This result demonstrates that the prêt-á-porter approach, using less-defined reporter-curdlan conjugates, is more advantageous than the traditional haute-couture approach with highly sophisticated hosts in particular in oligosaccharide sensing.

   @article{fukuhara2017oligosaccharide,
     title = {Oligosaccharide Sensing in Aqueous Media by Porphyrin--Curdlan Conjugates: A Prêt-á-Porter Rather Than Haute-Couture Approach},
     author = {Fukuhara, Gaku and Sasaki, Mayuko and Numata, Munenori and Mori, Tadashi and Inoue, Yoshihisa},
     journal = {Chem. Eur. J.},
     volume = {23},
     issue = {47},
     pages = {11272--11278},
     year = {2017},
     publisher = {Wiley Online Library},
     doi = {10.1002/chem.201701360},
     url = {https://doi.org/10.1002/chem.201701360},
     dimensions = {true},
     tab = {paper},
   }

8. 

   Temperature-driven planar chirality switching of a pillar [5] arene-based molecular universal joint

   Jiabin Yao, Wanhua Wu, Wenting Liang, Yujun Feng, Dayang Zhou, Jason J Chruma, Gaku Fukuhara, Tadashi Mori, Yoshihisa Inoue, and Cheng Yang^*

   Angew. Chem. Int. Ed., 2017, 129, 6973–6977.

   Article Abs DOI Bib

   The study of an enantiopure bicyclic pillar[5]arene-based molecular universal joint (MUJ) by single-crystal X-ray diffraction allowed for the first time the unequivocal assignment of the absolute configuration of a planar chiral pillar[5]arene by circular dichroism spectroscopy. Crucially, the absolute configuration of the MUJ was switched reversibly by temperature, with an accompanying sign inversion of the anisotropy factor that varied by as much as 0.03, which is the largest value ever reported. Mechanistically, the reversible chirality switching of the MUJ is driven by the threading/dethreading motion of the fused ring and hence is dependent on both the size and nature of the ring and the solvent employed, reflecting the critical balance between the self-complexation of the ring by pillar[5]arene, the solvation to the excluded ring, and the inclusion of solvent molecules in the cavity.

   @article{yao2017temperature,
     title = {Temperature-driven planar chirality switching of a pillar [5] arene-based molecular universal joint},
     author = {Yao, Jiabin and Wu, Wanhua and Liang, Wenting and Feng, Yujun and Zhou, Dayang and Chruma, Jason J and Fukuhara, Gaku and Mori, Tadashi and Inoue, Yoshihisa and Yang, Cheng},
     journal = {Angew. Chem. Int. Ed.},
     volume = {129},
     issue = {24},
     pages = {6973--6977},
     year = {2017},
     publisher = {Wiley Online Library},
     doi = {10.1002/anie.201702542},
     url = {https://doi.org/10.1002/anie.201702542},
     dimensions = {true},
     tab = {paper},
   }

9. 

   Absolute configuration determination through the unique intramolecular excitonic coupling in the circular dichroisms of o, p′-DDT and o, p′-DDD. A combined experimental and theoretical study

   Hiroki Tanaka, Yoshihisa Inoue, Takeshi Nakano, and Tadashi Mori^*

   Photochem. Photobiol. Sci., 2017, 16, 606–610.

   Article Abs DOI Bib

   Circular dichroisms (CDs) of the o,p′-isomers of 1,1,1-trichloro- and 1,1-dichloro-2,2-bis(chlorophenyl)ethanes (DDT and DDD) were investigated experimentally and theoretically. A series of strong Cotton effect peaks in a characteristic negative–negative–positive–negative, or its mirror-imaged, pattern were observed in the CD spectra of these persistent organic pollutants. The theoretical CD spectra at the SAC-CI/B95(d) and RI-CC2/def2-TZVPP levels well reproduced the experimental ones, enabling us to unambiguously assign the absolute configuration of (+)-DDT and (−)-DDD as S.

   @article{tanaka2017absolute,
     title = {Absolute configuration determination through the unique intramolecular excitonic coupling in the circular dichroisms of o, p′-DDT and o, p′-DDD. A combined experimental and theoretical study},
     author = {Tanaka, Hiroki and Inoue, Yoshihisa and Nakano, Takeshi and Mori, Tadashi},
     journal = {Photochem. Photobiol. Sci.},
     volume = {16},
     issue = {4},
     pages = {606--610},
     year = {2017},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/c6pp00438e},
     url = {https://doi.org/10.1039/c6pp00438e},
     dimensions = {true},
     tab = {paper},
   }

10. 

    Möbius aromatic [28] hexaphyrin germanium (IV) and tin (IV) complexes: Efficient formation of triplet excited states

    Mondo Izawa, Taeyeon Kim, Shin-ichiro Ishida, Takayuki Tanaka, Tadashi Mori, Dongho Kim^*, and Atsuhiro Osuka^*

    Angew. Chem. Int. Ed., 2017, 129, 4040–4044.

    Article Abs DOI Bib

    [28]Hexaphyrin GeIV and SnIV complexes were synthesized in high yields by reactions of [28]hexaphyrin with GeCl4 or SnCl4 in the presence of triethylamine. Both complexes display distinct 28π Möbius aromatic character and possess a trigonal bipyramidal geometry at the central GeIV or SnIV atom. The equatorial hydroxy group of the GeIV complex was smoothly exchanged with neutral nucleophiles, such as phenol derivatives and thiophenol, with retention of configuration. In the SnIV complex, intersystem crossing to the T1 state is remarkably enhanced owing to the effective heavy-atom effect, thus allowing the formation of the T1 tate in high yield. The T1 states of the GeIV and SnVI complexes were found to be antiaromatic on the basis of the transient absorption features in line with the Baird rule.

    @article{izawa2017mobius,
      title = {Möbius aromatic [28] hexaphyrin germanium (IV) and tin (IV) complexes: Efficient formation of triplet excited states},
      author = {Izawa, Mondo and Kim, Taeyeon and Ishida, Shin-ichiro and Tanaka, Takayuki and Mori, Tadashi and Kim, Dongho and Osuka, Atsuhiro},
      journal = {Angew. Chem. Int. Ed.},
      volume = {129},
      issue = {14},
      pages = {4040--4044},
      year = {2017},
      publisher = {Wiley Online Library},
      doi = {10.1002/anie.201700063},
      url = {https://doi.org/10.1002/anie.201700063},
      dimensions = {true},
      tab = {paper},
    }

11. 

    Sui generis helicene-based supramolecular chirogenic system: Enantioselective sensing, solvent control, and application in chiral group transfer reaction

    Mohammed Hasan, Vaibhav N Khose, Tadashi Mori, Victor Borovkov^*, and Anil V Karnik^*

    ACS Omega, 2017, 2, 592–598.

    Article Abs DOI Bib

    A novel dioxa[6]helicene-based supramolecular chirogenic system (1) as a specific chiral recognition host for enantiopure trans-1,2-cyclohexanediamine (2) is reported. Host 1 with an inherent free phenolic group and a (1S)-camphanate chiral handle on the opposite terminal rings of the helicene chromophore acted as an efficient turn on fluorescent sensor for S,S-2 with an excellent enantioselective factor, α = KSS/KRR = 6.3 in benzene. This specific host–guest interaction phenomenon is found to be solvent-dependent, which leads to an enantioselective chiral (camphanate) group transfer to the diamine guest molecule. In the case of R,R-2, the de value is up to 68% even at room temperature. Intriguingly, the induced helicity in dioxa[6]helicene diol 6, upon supramolecular hydrogen-bonding interactions, is of opposite sense with positive helicity for S,S-2 and negative helicity for R,R-2, as shown by circular dichroism spectroscopy and in combination with theoretical calculations. This chiral supramolecular system is found to be an excellent host–guest pair for enantiomeric recognition of 2, based on their electronic and steric factors.

    @article{hasan2017sui,
      title = {Sui generis helicene-based supramolecular chirogenic system: Enantioselective sensing, solvent control, and application in chiral group transfer reaction},
      author = {Hasan, Mohammed and Khose, Vaibhav N and Mori, Tadashi and Borovkov, Victor and Karnik, Anil V},
      journal = {ACS Omega},
      volume = {2},
      issue = {2},
      pages = {592--598},
      year = {2017},
      publisher = {ACS Publications},
      doi = {10.1021/acsomega.6b00522},
      url = {https://doi.org/10.1021/acsomega.6b00522},
      dimensions = {true},
      tab = {paper},
    }

12. 

    Temperature Dynamics of Single Molecular Antifreeze Protein

    Rio Okada, Tatsuya Arai, Daichi Fukami, Yuhuku Matsushita, Jae-won Chang, Hiroshi Sekiguchi, Noboru Ohta, Tadashi Mori, Masaki Nishijima, Keisuke Miyazawa, Takeshi Fukuma, Keigo Ikezaki, Sakae Tsuda, and Yuji C Sasaki

    Biophysical Journal, 2017, 112, 323a.

    Article Abs DOI Bib

    AntiFreeze Proteins (=AFPs) bind to a surface of ice crystals and inhibit their growth. Some living organisms; fishes, insects and fungus, at low-temperature environment have several different types of AFPs. AFPs protect their body from freezing damages. To clarify the antifreeze effect of lpAFP (isolated from longsnout poacher, a fish living in the sea of Okhotsk) at single molecular level, we performed the single molecular observation using diffracted X-ray tracking (=DXT). DXT is the method to observe single molecular motions using X-rays and gold nanocrystals as probe. Gold nanocrystals are labeled on AFPs, and when irradiated with X-rays, diffracted spots from gold nanocrystals can be observed. We can observe the motion of the AFPs by tracking these spots. We performed the DXT experiments at SPring-8 BL40XU, and the spatial and time resolutions are the order of milli-radian and micro-second. In this study, we used lpAFP isolated from longsnout poacher, and observed the temperature dependency of the lpAFP’s single molecular brownian motion. As a result, lpAFP’s motion increased at 5 °C. Next, to ensure the relationship between the adsorption property and the maximum brownian motion, we observed the temperature dependency of the adsorption affinity to AgI thin film as ice surface. As a result, the adsorption amount to AgI of lpAFP was the largest at 2°C. These two experiments suggest that there is a strong correlation between lpAFP’s molecular motion and adsorption property. We acquired the temperature dependency of lpAFP using other experiments; circular dichroism (CD), atomic force microscopy (AFM), dynamic light scattering (DLS), and small angle X-ray scattering (SAXS, performed at SPring-8 BL40B2). In poster session, we discuss the detail experimental procedure and results.

    @article{okada2017temperature,
      title = {Temperature Dynamics of Single Molecular Antifreeze Protein},
      author = {Okada, Rio and Arai, Tatsuya and Fukami, Daichi and Matsushita, Yuhuku and Chang, Jae-won and Sekiguchi, Hiroshi and Ohta, Noboru and Mori, Tadashi and Nishijima, Masaki and Miyazawa, Keisuke and Fukuma, Takeshi and Ikezaki, Keigo and Tsuda, Sakae and Sasaki, Yuji C},
      journal = {Biophysical Journal},
      volume = {112},
      issue = {3},
      pages = {323a},
      year = {2017},
      publisher = {Elsevier},
      doi = {10.1016/j.bpj.2016.11.1751},
      url = {https://doi.org/10.1016/j.bpj.2016.11.1751},
      dimensions = {true},
      tab = {paper},
    }

13. 

    Protonation-induced sign inversion of the cotton effects of pyridinophanes. A combined experimental and theoretical study

    Akinori Shimizu, Yoshihisa Inoue, and Tadashi Mori^*

    J. Phys. Chem. A, 2017, 121, 977–985.

    Article Abs DOI Bib

    The circular dichroisms (CDs) of planar chiral [2.2]- and [3.3]-pyridinophanes were investigated experimentally and theoretically. Strong multisignate Cotton effects, typical for cyclophane derivatives, were observed. The CD spectra of [2.2]- and [3.3]-paracyclophanes closely resembled in pattern each other, despite the much greater conformational variations in the latter. Upon protonation, both of the cyclophanes suffered dramatic CD spectral changes with accompanying complete sign inversion, which was attributed to the reversal of diploe moment of pyridinium versus pyridine moiety. This chiroptical property switching driven by protonation/deprotonation was temperature-dependent and hence applicable to thermal sensing. The protonated forms of pyridinophanes served as ideal model systems for studying the cation−π interactions and their effects on chiroptical properties. Thus, the molar CD (Δε) of the charge-transfer band of protonated [2.2]pyridinophane was 10-fold larger than that of protonated [3.3]pyridinophane, which exceeds the increased interplane electronic interactions assessed from the electronic coupling element values.

    @article{shimizu2017protonation,
      title = {Protonation-induced sign inversion of the cotton effects of pyridinophanes. A combined experimental and theoretical study},
      author = {Shimizu, Akinori and Inoue, Yoshihisa and Mori, Tadashi},
      journal = {J. Phys. Chem. A},
      volume = {121},
      issue = {5},
      pages = {977--985},
      year = {2017},
      publisher = {ACS Publications},
      doi = {10.1021/acs.jpca.6b12287},
      url = {https://doi.org/10.1021/acs.jpca.6b12287},
      dimensions = {true},
      tab = {paper},
    }

14. 

    Propeller chirality of boron heptaaryldipyrromethene: unprecedented supramolecular dimerization and chiroptical properties

    Masataka Toyoda, Yoshitane Imai, and Tadashi Mori^*

    J. Phys. Chem. Lett., 2017, 8, 42–48.

    Article Abs DOI Bib

    Chiral boron dipyrromethenes (BPs) enjoy high fluorescence efficiency at visible to near-IR wavelength regions with a reasonable range of dissymmetry factors. Here, we demonstrate that the (quasi)propeller chirality, similarly to hexagonal propeller in hexaarylbenzene, can be effectively induced in heptaarylated BP. In addition, supramolecular dimer was formed at low temperatures in nonpolar solvent, which exhibits strong bisignate Cotton effects at BP transitions (the couplet amplitude A = 193 M–1 cm–1) in the circular dichroism (CD). Due to the bulky substituents on the propeller blades, but with void space around boron atoms, BP chromophores in the dimer are aligned in a head-to-tail manner with a small torsion (φ ≈ 15°), to avoid fluorescence quenching usually observed in H-type dimer of BPs, exhibiting strong circularly polarized luminescence (CPL) signals (glum = 2.0 × 10–3, Φlum = 0.45). Such supramolecular dimer formation would be viewed as an alternative approach for designing and developing novel chiroptical materials.

    @article{toyoda2017propeller,
      title = {Propeller chirality of boron heptaaryldipyrromethene: unprecedented supramolecular dimerization and chiroptical properties},
      author = {Toyoda, Masataka and Imai, Yoshitane and Mori, Tadashi},
      journal = {J. Phys. Chem. Lett.},
      volume = {8},
      issue = {1},
      pages = {42--48},
      year = {2017},
      publisher = {ACS Publications},
      doi = {10.1021/acs.jpclett.6b02492},
      url = {https://doi.org/10.1021/acs.jpclett.6b02492},
      dimensions = {true},
      tab = {paper},
    }

15. 

    Asymmetric Photochemical Synthesis Based on Selective Excitation of Charge-Transfer Complexes

    Tadashi Mori^*

    J. Syn. Org. Chem., Jpn., 2017, 75, 144–152.

    Review Abs DOI Bib

    The use of photoreactions such as photoredox catalysts in asymmetric synthesis has been expansively recognized as expedient procedure over the past decade. In this paper, a potential application of photoreaction of Charge-Transfer (CT) complex for asymmetric synthesis is described. In chiral donor-acceptor systems, excitation wavelength, along with other environmental factors such as solvent polarity and temperature, plays more substantial role in determining the stereoselectivity of the photochemical outcomes. Accordingly, the excited CT complex produced upon the selective CT-band excitation behaves completely different from the conventional exciplex, which is formed by the direct excitation of donor or acceptor. Such unique wavelength effect, together with other entropic controls, may possibly come to be valuable means in asymmetric photochemical synthesis for the future.

    @article{mori2017asymmetric,
      title = {Asymmetric Photochemical Synthesis Based on Selective Excitation of Charge-Transfer Complexes},
      author = {Mori, Tadashi},
      journal = {J. Syn. Org. Chem., Jpn.},
      volume = {75},
      number = {2},
      pages = {144--152},
      year = {2017},
      doi = {10.5059/yukigoseikyokaishi.75.144},
      url = {https://doi.org/10.5059/yukigoseikyokaishi.75.144},
      dimensions = {true},
      tab = {review},
    }

16. Entropy Control of Reactions

    Tadashi Mori

    J. Syn. Org. Chem., Jpn., 2017, 75, 160.

    Review DOI Bib

    @article{mori2017entropy,
      title = {Entropy Control of Reactions},
      author = {Mori, Tadashi},
      journal = {J. Syn. Org. Chem., Jpn.},
      volume = {75},
      issue = {2},
      pages = {160},
      year = {2017},
      doi = {10.5059/yukigoseikyokaishi.75.160},
      url = {https://doi.org/10.5059/yukigoseikyokaishi.75.160},
      dimensions = {true},
      tab = {review}
    }

17. Chiral Photochemistry of Charge Transfer Complexes: Effect of Excitation Wavelength

    Tadashi Mori^*

    Symmetry, 2017, 28, 207–210.

    Bib

    @article{mori2017chiral,
      title = {Chiral Photochemistry of Charge Transfer Complexes: Effect of Excitation Wavelength},
      author = {Mori, Tadashi},
      journal = {Symmetry},
      volume = {28},
      issue = {2},
      pages = {207--210},
      year = {2017},
      publisher = {Symmetry: Culture and Science}
    }

2016

1. 

   Highly enantiodifferentiating site of human serum albumin for mediating photocyclodimerization of 2-anthracenecarboxylate elucidated by site-specific inhibition/quenching with xenon

   Masaki Nishijima^*, Tamara CS Pace, Cornelia Bohne, Tadashi Mori, Yoshihisa Inoue, and Takehiko Wada

   J. Photochem. Photobiol. A: Chem., 2016, 331, 89–94.

   Article Abs DOI Bib

   Complementary to the previous assignment of the first, second, and fourth binding sites of human serum albumin (HSA) for 2-anthracenecarboxylate (AC) and the subsequent mediation of AC photocyclodimerization, the site-specific inhibition of the enantiodifferentiation by xenon allowed us to assign the remaining third and fifth AC-binding sites to subdomains IB and IIIB, respectively. This study reveals a clearer picture of the binding and photochirogenic behavior of HSA and further expands the scope of bio-supramolecular photochirogenesis.

   @article{nishijima2016highly,
     title = {Highly enantiodifferentiating site of human serum albumin for mediating photocyclodimerization of 2-anthracenecarboxylate elucidated by site-specific inhibition/quenching with xenon},
     author = {Nishijima, Masaki and Pace, Tamara CS and Bohne, Cornelia and Mori, Tadashi and Inoue, Yoshihisa and Wada, Takehiko},
     journal = {J. Photochem. Photobiol. A: Chem.},
     volume = {331},
     pages = {89--94},
     year = {2016},
     publisher = {Elsevier},
     doi = {10.1016/j.jphotochem.2015.12.019},
     url = {https://doi.org/10.1016/j.jphotochem.2015.12.019},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Enhanced asymmetric photocycloaddition of anthracene tethered to maleate versus fumarate through non-fluorescent exciplex intermediate

   Makoto Ichikawa, Yoshihisa Inoue, and Tadashi Mori^*

   J. Photochem. Photobiol. A: Chem., 2016, 331, 102–109.

   Article Abs DOI Bib

   The asymmetric photocycloaddition of anthracene-tethered maleate with a small (S)-1-methylpropyl auxiliary at the peripheral position (1Z) underwent much faster than that of the corresponding fumarate (1E). The absolute configuration of the newly created chiral center in the major product was ambiguously assigned as (4S) by X-ray crystallographic as well as CD spectral studies. The facile E–Z photoisomerization was simultaneously observed for both 1Z and 1E, again much faster for 1Z. The concurrent electron transfer works as a quenching process and the fumarate acted as a better quencher than maleate in both intramolecular and intermolecular systems. The fluorescence quenching and quantum yield investigations also supported such facile electron transfer from excited-state anthracene to acceptor in the singlet manifold. Observed diastereoselectivities in the photocycloaddition of 1Z and 1E were moderate but substantial (5–12% de), given the fact that the chiral auxiliary is introduced at the remote position from the reaction center (4-bond separation). The non-fluorescent exciplex, probably in a triplet manifold derived from the singlet exciplex, plays a crucial role in this efficient cyclization process, affording a biradical intermediate, that can either dissociate or undergo second bond formation to afford a diastereomeric trans adduct 2. The diastereoselectivity was higher in less polar solvents, suggesting the polar nature of the exciplex.

   @article{ichikawa2016enhanced,
     title = {Enhanced asymmetric photocycloaddition of anthracene tethered to maleate versus fumarate through non-fluorescent exciplex intermediate},
     author = {Ichikawa, Makoto and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {J. Photochem. Photobiol. A: Chem.},
     volume = {331},
     pages = {102--109},
     year = {2016},
     publisher = {Elsevier},
     doi = {10.1016/j.jphotochem.2015.09.001},
     url = {https://doi.org/10.1016/j.jphotochem.2015.09.001},
     dimensions = {true},
     tab = {paper},
   }

3. 

   Critical control by scaffold flexibility achieved in diastereodifferentiating photocyclodimerization of 2-anthracenecarboxylate

   Gaku Fukuhara^*, Kazuhiro Iida, Tadashi Mori, and Yoshihisa Inoue

   J. Photochem. Photobiol. A: Chem., 2016, 331, 76–83.

   Article Abs DOI Bib

   By progressively increasing the flexibility of chiral vicinal diol scaffold (from rigid cyclic tetrasaccharide to flexible 2,3-butanediol via glucose and trans-1,2-cyclohexandiol) in the diastereodifferentiating photocyclodimerization to head-to-head (HH) dimers of 2-anthracenecarboxylate on the scaffold, the anti/syn preference was dramatically inverted from 42:1 to 1:12, while the enantiomeric excess of the chiral anti-HH dimer was consistently kept high at >99% due to the excited-state dynamics that strongly disfavors the si–si enantiotopic face attack against the antipodal re–re face attack, exclusively affording the (P)-enantiomer.

   @article{fukuhara2016critical,
     title = {Critical control by scaffold flexibility achieved in diastereodifferentiating photocyclodimerization of 2-anthracenecarboxylate},
     author = {Fukuhara, Gaku and Iida, Kazuhiro and Mori, Tadashi and Inoue, Yoshihisa},
     journal = {J. Photochem. Photobiol. A: Chem.},
     volume = {331},
     pages = {76--83},
     year = {2016},
     publisher = {Elsevier},
     doi = {10.1016/j.jphotochem.2016.01.016},
     url = {https://doi.org/10.1016/j.jphotochem.2016.01.016},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Yoshihisa Inoue—A researcher’s quest for photochirogenesis

   Tadashi Mori^*, Gaku Fukuhara, and Takehiko Wada

   J. Photochem. Photobiol. A: Chem., 2016, 331, 2–7.

   Article Abs DOI Bib

   This issue of Journal of Photochemistry and Photobiology A: Chemistry is dedicated to Prof. Yoshihisa Inoue, a man of “photochirogenesis”, and his enthusiastic attitude toward chemistry. We feel highly privileged and deeply honored that we have been serving as guest editors for this special issue, honoring his retirement from Osaka University in 2015 and continued impact on supramolecular chemistry and photochemistry.

   @article{mori2016yoshihisa,
     title = {Yoshihisa Inoue—A researcher’s quest for photochirogenesis},
     author = {Mori, Tadashi and Fukuhara, Gaku and Wada, Takehiko},
     journal = {J. Photochem. Photobiol. A: Chem.},
     volume = {331},
     pages = {2--7},
     year = {2016},
     publisher = {Elsevier},
     doi = {10.1016/j.jphotochem.2016.08.006},
     url = {https://doi.org/10.1016/j.jphotochem.2016.08.006},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Orbital Control of Photochemical Rearrangement of 4-Aryl-1, 1-dicyano-1-butenes through the Hyperconjugative Substitution on the Linker Chain

   Nobuo Matsuki, Yoshihisa Inoue, and Tadashi Mori^*

   J. Phys. Chem. Lett., 2016, 7, 4957–4961.

   Article Abs DOI Bib

   Hyperconjugative interaction was demonstrated to play a vital role in the photochemistry of 4-aryl-1,1-dicyano-1-butenes. Thus a simple substituent on the benzylic position effectively induced a new photoreactivity to afford an allylic rearrangement product that is not obtained for the parent substrate. The natural bond orbital analysis was employed to reveal the enhanced relative contributions of hyperconjugation in the excited state, which dramatically alter the photochemical outcomes not only by reducing the strength of the allylic/benzylic bond but more crucially by affecting the conformer distribution.

   @article{matsuki2016orbital,
     title = {Orbital Control of Photochemical Rearrangement of 4-Aryl-1, 1-dicyano-1-butenes through the Hyperconjugative Substitution on the Linker Chain},
     author = {Matsuki, Nobuo and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {J. Phys. Chem. Lett.},
     volume = {7},
     issue = {24},
     pages = {4957--4961},
     year = {2016},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpclett.6b02632},
     url = {https://doi.org/10.1021/acs.jpclett.6b02632},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Optical activity and optical anisotropy in photomechanical crystals of chiral salicylidenephenylethylamines

   Akifumi Takanabe, Masahito Tanaka, Kohei Johmoto, Hidehiro Uekusa, Tadashi Mori, Hideko Koshima^*, and Toru Asahi^*

   J. Am. Chem. Soc., 2016, 138, 15066–15077.

   Article Abs DOI Bib

   Introducing chirality into photomechanical crystals is beneficial for the diversification of mechanical motion. Measurement of the chiroptical and optical anisotropic properties of chiral crystals is indispensable for evaluating photomechanical crystals. The platelike crystals of S- and R-enantiomers of photochromic N-3,5-di-tert-butylsalicylidene-1-phenylethylamine in enol form (enol-(S)-1 and enol-(R)-1) caused bending motion with twisting upon ultraviolet (UV) light irradiation, due to shrinkage along the length and width directions of the irradiated surface, based on the optimized crystal structure of the photoisomerized trans-keto-(S)-1. By employing the generalized high-accuracy universal polarimeter (G-HAUP), optical anisotropic (linear birefringence, LB; linear dichroism, LD) as well as chiroptical (circular birefringence, CB; circular dichroism, CD) spectra of both the enantiomeric crystals on the (001) face were simultaneously measured before and under continuous UV irradiation. The LD peak was observed at 330 nm in the negative sign, derived from the π–π* transition of the intramolecularly hydrogen-bonded salicylidenimino moiety. The CD spectra of the S and R crystals revealed the negative and positive Cotton effect at 330 nm, respectively, and new peaks appeared at 460 nm under UV light irradiation due to photoisomerization to the S and Rtrans-keto isomers at around 10% conversion. The CB and CD spectra evaluated by the HAUP measurement were opposite to those measured in the hexane solution, as well as those simulated by quantum chemical calculation. The dissymmetry parameter, g, of the enol-(S)-1 crystal along the c axis (0.013) was approximately 10 times larger than the g values in the solution (0.0010) and by calculation (0.0016).

   @article{takanabe2016optical,
     title = {Optical activity and optical anisotropy in photomechanical crystals of chiral salicylidenephenylethylamines},
     author = {Takanabe, Akifumi and Tanaka, Masahito and Johmoto, Kohei and Uekusa, Hidehiro and Mori, Tadashi and Koshima, Hideko and Asahi, Toru},
     journal = {J. Am. Chem. Soc.},
     volume = {138},
     issue = {45},
     pages = {15066--15077},
     year = {2016},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.6b09633},
     url = {https://doi.org/10.1021/jacs.6b09633},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Electrostatically promoted dynamic hybridization of glucans with cationic polythiophene

   Gaku Fukuhara^*, Mami Imai, Denis Fuentealba, Yuki Ishida, Hiroki Kurohara, Cheng Yang, Tadashi Mori, Hiroshi Uyama, Cornelia Bohne, and Yoshihisa Inoue

   Org. Biomol. Chem., 2016, 14, 9741–9750.

   Article Abs DOI Bib

   Hybridizing natural macromolecules with synthetic polymers is an efficient general method for constructing sophisticated supramolecular architectures. To comprehensively elucidate the controversial hybridization mechanism of glucans with synthetic polymers, the hybridization behaviors of triple-stranded curdlan (Cur) and schizophyllan (SPG) with cationic polythiophene (PyPT) were investigated in aqueous DMSO solutions by using UV-vis, circular dichroism (CD), fluorescence, fluorescence excitation, and NMR spectroscopy methods, as well as theoretical calculations, dynamic light scattering, and zeta potential measurements. Upon mixing with glucan, a hetero-triplex formed, which was dynamic and greatly accelerated by heating and by adding a base or a salt. The hetero-triplex disassembled into a hetero-duplex in highly basic solutions. Thus, polycationic polymers, such as PyPT, are expected to serve as a versatile tool for unzipping glucan homo-triplexes and promoting subsequent hybridization in aqueous solution, while the detailed mechanism elucidated in the present study contributes to the rational design of hybridization partners.

   @article{fukuhara2016electrostatically,
     title = {Electrostatically promoted dynamic hybridization of glucans with cationic polythiophene},
     author = {Fukuhara, Gaku and Imai, Mami and Fuentealba, Denis and Ishida, Yuki and Kurohara, Hiroki and Yang, Cheng and Mori, Tadashi and Uyama, Hiroshi and Bohne, Cornelia and Inoue, Yoshihisa},
     journal = {Org. Biomol. Chem.},
     volume = {14},
     number = {41},
     pages = {9741--9750},
     year = {2016},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/c6ob01353h},
     url = {https://doi.org/10.1039/c6ob01353h},
     dimensions = {true},
     tab = {paper},
   }

8. 

   Supramolecular photochirogenesis with a higher-order complex: highly accelerated exclusively head-to-head photocyclodimerization of 2-anthracenecarboxylic acid via 2: 2 complexation with prolinol

   Yuko Kawanami, Shin-ya Katsumata, Masaki Nishijima, Gaku Fukuhara, Kaori Asano, Takeyuki Suzuki, Cheng Yang, Asao Nakamura, Tadashi Mori, and Yoshihisa Inoue^*

   J. Am. Chem. Soc., 2016, 138, 12187–12201.

   Article Abs DOI Bib

   An unprecedented 2:2 complex was shown to intervene in the enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (A) mediated by a hydrogen-bonding template l-prolinol (P) to accelerate the formation of chiral anti-head-to-head and achiral syn-head-to-head cyclodimers in >99% combined yield with enhanced enantioselectivities of up to 72% ee for the former. The supramolecular complexation and photochirogenic behaviors, as well as the plausible structures, of intervening Am·Pn complexes (m, n = 1 or 2) were elucidated by combined theoretical and experimental spectroscopic, photophysical, and photochemical studies. Furthermore, the photochemical chiral amplification was achieved for the first time by utilizing the preferential 2:2 complexation of A with homochiral P to give normalized product enantioselectivities higher than those of the template used. The present strategy based on the higher-order hydrogen-bonding motif, which is potentially applicable to a variety of carboxylic acids and β-aminoalcohols, is not only conceptually new and expandable to other (photo)chirogenic and sensing systems but also may serve as a versatile tool for achieving photochemical asymmetric amplification and constructing chiral functional supramolecular architectures.

   @article{kawanami2016supramolecular,
     title = {Supramolecular photochirogenesis with a higher-order complex: highly accelerated exclusively head-to-head photocyclodimerization of 2-anthracenecarboxylic acid via 2: 2 complexation with prolinol},
     author = {Kawanami, Yuko and Katsumata, Shin-ya and Nishijima, Masaki and Fukuhara, Gaku and Asano, Kaori and Suzuki, Takeyuki and Yang, Cheng and Nakamura, Asao and Mori, Tadashi and Inoue, Yoshihisa},
     journal = {J. Am. Chem. Soc.},
     volume = {138},
     number = {37},
     pages = {12187--12201},
     year = {2016},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.6b05598},
     url = {https://doi.org/10.1021/jacs.6b05598},
     dimensions = {true},
     tab = {paper},
   }

9. 

   Combined Experimental and Theoretical Investigations on Optical Activities of Möbius Aromatic and Möbius Antiaromatic Hexaphyrin Phosphorus Complexes

   Tadashi Mori^*, Takayuki Tanaka, Tomohiro Higashino, Kota Yoshida, and Atsuhiro Osuka

   J. Phys. Chem. A, 2016, 120, 4241–4248.

   Article Abs DOI Bib

   Intrinsically chiral Möbius aromatic [28]hexaphyrin monophosphorus(V) and Möbius antiaromatic [30]hexaphyrin bisphosphorus(V) complexes have been optically resolved and their absolute configurations (ACs) were determined by combined experimental and theoretical investigations on their circular dichroisms (CDs). First elutes in chiral HPLC exhibited strong positive Cotton effects (CEs) at the B-band, characteristic for the ML configurations in their Möbius strips. Weak CEs at the Q-band, if attainable, complemented their AC assignment. The whole CD pattern and intensity were well reproduced by time-dependent approximate coupled cluster theory using model systems that omit five outward meso-aryl substituents (inward-meso-retained model), providing a solid basis for AC assignment. The cost efficient TD-DFT method with appropriate functionals for fully substituted (nontruncated) complexes well reproduced CEs around the B-band (but less satisfactory at the Q-band), also allows the rapid AC estimation for their Möbius strips. Observed difference in CDs between aromatic and antiaromatic hexaphyrins were better interpreted by their shifts in energy levels and altered interactions of relevant molecular orbitals, rather than small differences in Möbius geometries nor aromatic/antiaromatic character, despite the correlations recently claimed in planar π-systems.

   @article{mori2016combined,
     title = {Combined Experimental and Theoretical Investigations on Optical Activities of Möbius Aromatic and Möbius Antiaromatic Hexaphyrin Phosphorus Complexes},
     author = {Mori, Tadashi and Tanaka, Takayuki and Higashino, Tomohiro and Yoshida, Kota and Osuka, Atsuhiro},
     journal = {J. Phys. Chem. A},
     volume = {120},
     number = {24},
     pages = {4241--4248},
     year = {2016},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.6b03978},
     url = {https://doi.org/10.1021/acs.jpca.6b03978},
     dimensions = {true},
     tab = {paper},
   }

10. 

    Inherently chiral azonia [6] helicene-modified β-cyclodextrin: Synthesis, characterization, and chirality sensing of underivatized amino acids in water

    Qinfei Huang, Liangwei Jiang, Wenting Liang, Jianchang Gui, Dingguo Xu, Wanhua Wu, Yoshito Nakai, Masaki Nishijima, Gaku Fukuhara, Tadashi Mori, Yoshihisa Inoue^*, and Cheng Yang^*

    J. Org. Chem., 2016, 81, 3430–3434.

    Article Abs DOI Bib

    The (P)- and (M)-3-azonia[6]helicenyl β-cyclodextrins exhibit l/d selectivities of up to 12.4 and P/M preferences of up to 28.2 upon complexation with underivatized proteinogenic amino acids in aqueous solution at pH 7.3.

    @article{huang2016inherently,
      title = {Inherently chiral azonia [6] helicene-modified $\beta$-cyclodextrin: Synthesis, characterization, and chirality sensing of underivatized amino acids in water},
      author = {Huang, Qinfei and Jiang, Liangwei and Liang, Wenting and Gui, Jianchang and Xu, Dingguo and Wu, Wanhua and Nakai, Yoshito and Nishijima, Masaki and Fukuhara, Gaku and Mori, Tadashi and Inoue, Yoshihisa and Yang, Cheng},
      journal = {J. Org. Chem.},
      volume = {81},
      number = {8},
      pages = {3430--3434},
      year = {2016},
      publisher = {ACS Publications},
      doi = {10.1021/acs.joc.6b00130},
      url = {https://doi.org/10.1021/acs.joc.6b00130},
      dimensions = {true},
      tab = {paper},
    }

11. 

    Toroidal interaction and propeller chirality of hexaarylbenzenes. Dynamic domino inversion revealed by combined experimental and theoretical circular dichroism studies

    Tomoyo Kosaka, Yoshihisa Inoue, and Tadashi Mori^*

    J. Phys. Chem. Lett., 2016, 7, 783–788.

    Article Abs DOI Bib

    Hexaarylbenzenes (HABs) have greatly attracted much attention due to their unique propeller-shaped structure and potential application in materials science, such as liquid crystals, molecular capsules/rotors, redox materials, nonlinear optical materials, as well as molecular wires. Less attention has however been paid to their propeller chirality. By introducing small point-chiral group(s) at the periphery of HABs, propeller chirality was effectively induced, provoking strong Cotton effects in the circular dichroism (CD) spectrum. Temperature and solvent polarity manipulate the dynamics of propeller inversion in solution. As such, whizzing toroids become more substantial in polar solvents and at an elevated temperature, where radial aromatic rings (propeller blades) prefer orthogonal alignment against the central benzene ring (C6 core), maximizing toroidal interactions.

    @article{kosaka2016toroidal,
      title = {Toroidal interaction and propeller chirality of hexaarylbenzenes. Dynamic domino inversion revealed by combined experimental and theoretical circular dichroism studies},
      author = {Kosaka, Tomoyo and Inoue, Yoshihisa and Mori, Tadashi},
      journal = {J. Phys. Chem. Lett.},
      volume = {7},
      number = {5},
      pages = {783--788},
      year = {2016},
      publisher = {ACS Publications},
      doi = {10.1021/acs.jpclett.6b00179},
      url = {https://doi.org/10.1021/acs.jpclett.6b00179},
      dimensions = {true},
      tab = {paper},
    }

12. 

    Long-lived triplet excited states of bent-shaped pentacene dimers by intramolecular singlet fission

    Takao Sakuma, Hayato Sakai, Yasuyuki Araki, Tadashi Mori, Takehiko Wada, Nikolai V Tkachenko^*, and Taku Hasobe^*

    J. Phys. Chem. A, 2016, 120, 1867–1875.

    Article Abs DOI Bib

    Intramolecular singlet fission (ISF) is a promising photophysical process to construct more efficient light energy conversion systems as one excited singlet state converts into two excited triplet states. Herein we synthesized and evaluated bent-shaped pentacene dimers as a prototype of ISF to reveal intrinsic characters of triplet states (e.g., lifetimes of triplet excited states). In this study, meta-phenylene-bridged TIPS-pentacene dimer (PcD-3Ph) and 2,2′-bipheynyl bridged TIPS-pentacene dimer (PcD-Biph) were newly synthesized as bent-shaped dimers. In the steady-state spectroscopy, absorption and emission bands of these dimers were fully characterized, suggesting the appropriate degree of electronic coupling between pentacene moieties in these dimers. In addition, the electrochemical measurements were also performed to check the electronic interaction between two pentacene moieties. Whereas the successive two oxidation peaks owing to the delocalization were observed in a directly linked-pentacene dimer (PcD) by a single bond, the cyclic voltammograms in PcD-Biph and PcD-3Ph implied the weaker interaction compared to that of p-phenylene-bridged TIPS-pentacene dimer (PcD-4Ph) and PcD. The femtosecond and nanosecond transient absorption spectra clearly revealed the slower ISF process in bent-shaped pentacene dimers (PcD-Biph and PcD-3Ph), more notably, the slower relaxation of the excited triplet states in PcD-Biph and PcD-3Ph. Namely, the quantum yields of triplet states (ΦT) by ISF approximately remain constant (ca. 180–200%) in all dimer systems, whereas the lifetimes of the triplet excited states became much longer (up to 360 ns) in PcD-Biph as compared to PcD-4Ph (15 ns). Additionally, the lifetimes of the corresponding triplet states in PcD-Biph and PcD-3Ph were sufficiently affected by solvent viscosity. In particular, the lifetimes of PcD-Biph triplet state in THF/paraffin (1.0 μs) increased up to approximately three times as compared to that in THF (360 ns), whereas those of PcD-4Ph were quite similar in both solvent.

    @article{sakuma2016long,
      title = {Long-lived triplet excited states of bent-shaped pentacene dimers by intramolecular singlet fission},
      author = {Sakuma, Takao and Sakai, Hayato and Araki, Yasuyuki and Mori, Tadashi and Wada, Takehiko and Tkachenko, Nikolai V and Hasobe, Taku},
      journal = {J. Phys. Chem. A},
      volume = {120},
      number = {11},
      pages = {1867--1875},
      year = {2016},
      publisher = {ACS Publications},
      doi = {10.1021/acs.jpca.6b00988},
      url = {https://doi.org/10.1021/acs.jpca.6b00988},
      dimensions = {true},
      tab = {paper},
    }

13. 

    Enantioselective [4+4] photodimerization of anthracene-2,6-dicarboxylic acid mediated by a C2-symmetric chiral template

    Mark M Maturi, Gaku Fukuhara, Koichiro Tanaka, Yuko Kawanami, Tadashi Mori, Yoshihisa Inoue^*, and Thorsten Bach

    Chem. Commun., 2016, 52, 1032–1035.

    Article Abs DOI Bib

    A chiral template was constructed from 7-ethynyl-1,5,7-trimethyl-3-azabicyclo[3.3.1]nonan-2-one by Sonogashira cross-coupling with 4,4′′-diiodoterphenyl and was shown to bind the title compound strongly by hydrogen bonding resulting in enantioselectivities of up to 55% enantiomeric excess (ee) in the [4+4] anthracene photodimerization.

    @article{maturi2016enantioselective,
      title = {Enantioselective [4+4] photodimerization of anthracene-2,6-dicarboxylic acid mediated by a C2-symmetric chiral template},
      author = {Maturi, Mark M and Fukuhara, Gaku and Tanaka, Koichiro and Kawanami, Yuko and Mori, Tadashi and Inoue, Yoshihisa and Bach, Thorsten},
      journal = {Chem. Commun.},
      volume = {52},
      number = {5},
      pages = {1032--1035},
      year = {2016},
      publisher = {Royal Society of Chemistry},
      doi = {10.1039/c5cc09107a},
      url = {https://doi.org/10.1039/c5cc09107a},
      dimensions = {true},
      tab = {paper},
    }

14. 

    Dynamic propeller conformation for the unprecedentedly high degree of chiral amplification of supramolecular helices

    Taehoon Kim, Tadashi Mori, Takuzo Aida, and Daigo Miyajima^*

    Chem. Sci., 2016, 7, 6689–6694.

    Article Abs DOI Bib

    An unprecedentedly high degree of chiral amplification of supramolecular helices in a sergeants and soldiers system was realized using a propeller-shaped molecule, triphenylamine (TPA), as the monomer. One sergeant controlled the handedness of 500 soldiers in supramolecular helices. We further demonstrated that a TPA derivative could switch its role from sergeant to soldier and vice versa depending on its partners. These achievements could be realized using the dynamic propeller conformation of TPA and provide new insights into supramolecular assemblies and the supramolecular chiral amplification of helices.

    @article{kim2016dynamic,
      title = {Dynamic propeller conformation for the unprecedentedly high degree of chiral amplification of supramolecular helices},
      author = {Kim, Taehoon and Mori, Tadashi and Aida, Takuzo and Miyajima, Daigo},
      journal = {Chem. Sci.},
      volume = {7},
      number = {11},
      pages = {6689--6694},
      year = {2016},
      publisher = {Royal Society of Chemistry},
      doi = {10.1039/c6sc02814d},
      url = {https://doi.org/10.1039/c6sc02814d},
      dimensions = {true},
      tab = {paper},
    }

2015

1. 

   Nickel (0)/N-heterocyclic carbene-catalyzed asymmetric [2+ 2+ 2] cycloaddition of two enones and an alkyne: Access to cyclohexenes with four contiguous stereogenic centers

   Ravindra Kumar, Hiromu Tokura, Akira Nishimura, Tadashi Mori, Yoichi Hoshimoto, Masato Ohashi, and Sensuke Ogoshi^*

   Org. Lett., 2015, 17, 6018–6021.

   Article Abs DOI Bib

   A nickel(0)/chiral N-heterocyclic carbene (NHC)-catalyzed fully intermolecular, enantioselective [2 + 2 + 2] cycloaddition of two enones and an alkyne has been developed to access enantioenriched cyclohexenes. A single diastereomer was obtained with a successive generation of four contiguous stereogenic centers. The absolute configuration of cyclohexene derivative 3aa was determined by X-ray diffraction and circular dichroism (CD) spectral studies.

   @article{kumar2015nickel,
     title = {Nickel (0)/N-heterocyclic carbene-catalyzed asymmetric [2+ 2+ 2] cycloaddition of two enones and an alkyne: Access to cyclohexenes with four contiguous stereogenic centers},
     author = {Kumar, Ravindra and Tokura, Hiromu and Nishimura, Akira and Mori, Tadashi and Hoshimoto, Yoichi and Ohashi, Masato and Ogoshi, Sensuke},
     journal = {Org. Lett.},
     volume = {17},
     number = {24},
     pages = {6018--6021},
     year = {2015},
     publisher = {ACS Publications},
     doi = {10.1021/acs.orglett.5b02983},
     url = {https://doi.org/10.1021/acs.orglett.5b02983},
     dimensions = {true},
     tab = {paper},
   }

2. 

   Excited-state dynamics achieved ultimate stereocontrol of photocyclodimerization of anthracenecarboxylates on a glucose scaffold

   Gaku Fukuhara^*, Kazuhiro Iida, Yuko Kawanami, Hidekazu Tanaka, Tadashi Mori, and Yoshihisa Inoue^*

   J. Am. Chem. Soc., 2015, 137, 15007–15014.

   Article Abs DOI Bib

   Near-perfect stereoselectivity was attained in the diastereodifferentiating [4 + 4] photocyclodimerization of 2-anthracenecarboxylates tethered to a glucose scaffold not by thermodynamically tuning the conformer equilibrium in the ground state but by kinetically controlling the conformer dynamics and reactivity in the excited state, which enabled us, after removal of the scaffold, to obtain a single enantiomer of chiral anti-head-to-head-cyclodimer in >99% optical and 96% chemical yield from an ensemble of four precursor conformers.

   @article{fukuhara2015excited,
     title = {Excited-state dynamics achieved ultimate stereocontrol of photocyclodimerization of anthracenecarboxylates on a glucose scaffold},
     author = {Fukuhara, Gaku and Iida, Kazuhiro and Kawanami, Yuko and Tanaka, Hidekazu and Mori, Tadashi and Inoue, Yoshihisa},
     journal = {J. Am. Chem. Soc.},
     volume = {137},
     number = {47},
     pages = {15007--15014},
     year = {2015},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.5b09775},
     url = {https://doi.org/10.1021/jacs.5b09775},
     dimensions = {true},
     tab = {paper},
   }

3. 

   pH-independent charge resonance mechanism for UV protective functions of shinorine and related mycosporine-like amino acids

   Keisuke Matsuyama, Jun Matsumoto, Shogo Yamamoto, Keisuke Nagasaki, Yoshihisa Inoue, Masaki Nishijima, and Tadashi Mori^*

   J. Phys. Chem. A, 2015, 119, 12722–12729.

   Article Abs DOI Bib

   The UV-protective ability of mycosporine-like amino acids (MAAs) has been well documented and is believed to serve as a protecting agent for marine organisms from solar radiation. However, the effective UV absorption by MAAs has not been well correlated to MAA (neutral) structures. In this study, the origin of UV-protecting ability of MAAs was elucidated by experimental and theoretical spectroscopic investigations. The absorption maxima of mycosporine–glycine and shinorine in the UVA region were practically unaffected over a wide range of pH 4–10 and only slightly blue-shifted at pH 1–2. It was revealed that the zwitterionic nature of the amino acid residue facilitates the protonation to the chromophoric 3-aminocyclohexenone and 1-amino-3-iminocyclohexene moieties and the operation of the charge resonance in the protonated species well accounts for their allowed low-energy transitions in the UVA region. The RI-CC2/TZVP calculations on model systems in their protonated forms well reproduced the observed transition energies and oscillator strengths of MAAs, only with insignificant systematic overestimations of the both values. The slight hypsochromic shifts at pH 1–2 were explained by (partial) protonation to a carboxylate anion in the amino acid residue, as confirmed by theory. Fluorescence spectral investigations of shinorine were also performed for the first time in water to confirm the effective nonradiative deactivation. Consequently, this study unequivocally demonstrated that the 3-aminocyclohexenone as well as 1-amino-3-iminocyclohexene moieties, which are readily protonated at a wide range of pH, are responsible for the UV-protective ability of aqueous solution of MAAs.

   @article{matsuyama2015ph,
     title = {pH-independent charge resonance mechanism for UV protective functions of shinorine and related mycosporine-like amino acids},
     author = {Matsuyama, Keisuke and Matsumoto, Jun and Yamamoto, Shogo and Nagasaki, Keisuke and Inoue, Yoshihisa and Nishijima, Masaki and Mori, Tadashi},
     journal = {J. Phys. Chem. A},
     volume = {119},
     number = {51},
     pages = {12722--12729},
     year = {2015},
     publisher = {ACS Publications},
     doi = {10.1021/acs.jpca.5b09988},
     url = {https://doi.org/10.1021/acs.jpca.5b09988},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Helix sense-selective supramolecular polymerization seeded by a one-handed helical polymeric assembly

   Wei Zhang, Wusong Jin, Takanori Fukushima^*, Tadashi Mori, and Takuzo Aida^*

   . Am. Chem. Soc., 2015, 137, 13792–13795.

   Article Abs DOI Bib

   Helix sense-selective supramolecular polymerization was achieved using a one-handed helical nanotubular polymeric assembly as a seed. First, bipyridine (BPY)-appended achiral hexabenzocoronene (BPYHBC) was copolymerized noncovalently with chiral BPYHBCS (or BPYHBCR) at a molar ratio of 9:1, which, via the sergeants-and-soldiers effect, afforded a P-helical (or M-helical) nanotube, which was then treated with Cu2+ to transform into structurally robust (BPY)CuNT(P) (or (BPY)CuNT(M)) with a Cu2+/BPY coordination polymer shell. Helical seeds (BPY)CuNT(P) and (BPY)CuNT(M) brought about the controlled assembly of fluorinated chiral FHBCS and FHBCR as well as achiral FHBC to yield one-handed helical nanotubular supramolecular block copolymers, in which the helical senses of the newly formed block segments were solely determined by those of the helical seeds employed. Noteworthy, FHBCS and FHBCR alone without the helical seeds form ill-defined agglomerates. Attempted supramolecular polymerization of a racemic mixture of FHBCS and FHBCR from (BPY)CuNT(P) (or (BPY)CuNT(M)) resulted in its chiral separation, affording P-helical (or M-helical) diastereomeric block segments composed of FHBCS and FHBCR with different thermodynamic properties.

   @article{zhang2015helix,
     title = {Helix sense-selective supramolecular polymerization seeded by a one-handed helical polymeric assembly},
     author = {Zhang, Wei and Jin, Wusong and Fukushima, Takanori and Mori, Tadashi and Aida, Takuzo},
     journal = {. Am. Chem. Soc.},
     volume = {137},
     number = {43},
     pages = {13792--13795},
     year = {2015},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.5b09878},
     url = {https://doi.org/10.1021/jacs.5b09878},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Metal–Organic Nanotube with Helical and Propeller-Chiral Motifs Composed of a C 10-Symmetric Double-Decker Nanoring

   Hiroshi Yamagishi, Takahiro Fukino^*, Daisuke Hashizume, Tadashi Mori, Yoshihisa Inoue, Takaaki Hikima, Masaki Takata, and Takuzo Aida^*

   J. Am. Chem. Soc., 2015, 137, 7628–7631.

   Article Abs DOI Bib

   Coassembly of an achiral ferrocene-cored tetratopic pyridyl ligand (FcL) with AgBF4 in CH2Cl2/MeCN (7:3 v/v) containing chiral Bu4N+ (+)- or (−)-menthylsulfate (MS*–) results in the formation of an “optically active” metal–organic nanotube (FcNT) composed of a C10-symmetric double-decker nanoring featuring 10 FcL units and 20 Ag+ ions. The circular dichroism spectrum of FcNT along with its 2D X-ray diffraction (2D XRD) pattern indicates that the constituent metal–organic nanorings in FcNT stack one-handed helically on top of each other. A crystal structure of the dimeric double-decker model complex (Ag2(FcL′)2) from a ditopic ferrocene ligand (FcL′) and AgBF4 allowed for confirming the binding of MS*– onto the Ag+ center of the complex. The results of detailed spectroscopic studies indicate that in its double-decker aromatic arrays, FcNT possibly possesses propeller-chiral twists in addition to the helically chiral structure, where the former is considerably more dynamic than the latter. Notably, both chiral structural motifs responded nonlinearly to an enantiomeric excess of MS*– (majority rule) though with no stereochemical influence on one another.

   @article{yamagishi2015metal,
     title = {Metal--Organic Nanotube with Helical and Propeller-Chiral Motifs Composed of a C 10-Symmetric Double-Decker Nanoring},
     author = {Yamagishi, Hiroshi and Fukino, Takahiro and Hashizume, Daisuke and Mori, Tadashi and Inoue, Yoshihisa and Hikima, Takaaki and Takata, Masaki and Aida, Takuzo},
     journal = {J. Am. Chem. Soc.},
     volume = {137},
     number = {24},
     pages = {7628--7631},
     year = {2015},
     publisher = {ACS Publications},
     doi = {10.1021/jacs.5b04386},
     url = {https://doi.org/10.1021/jacs.5b04386},
     dimensions = {true},
     tab = {paper},
   }

6. 

   A rational strategy for the realization of chain-growth supramolecular polymerization

   Jiheong Kang, Daigo Miyajima^*, Tadashi Mori, Yoshihisa Inoue, Yoshimitsu Itoh, and Takuzo Aida^*

   Science, 2015, 347, 646–651.

   Article Abs DOI Bib

   Over the past decade, major progress in supramolecular polymerization has had a substantial effect on the design of functional soft materials. However, despite recent advances, most studies are still based on a preconceived notion that supramolecular polymerization follows a step-growth mechanism, which precludes control over chain length, sequence, and stereochemical structure. Here we report the realization of chain-growth polymerization by designing metastable monomers with a shape-promoted intramolecular hydrogen-bonding network. The monomers are conformationally restricted from spontaneous polymerization at ambient temperatures but begin to polymerize with characteristics typical of a living mechanism upon mixing with tailored initiators. The chain growth occurs stereoselectively and therefore enables optical resolution of a racemic monomer.

   @article{kang2015rational,
     title = {A rational strategy for the realization of chain-growth supramolecular polymerization},
     author = {Kang, Jiheong and Miyajima, Daigo and Mori, Tadashi and Inoue, Yoshihisa and Itoh, Yoshimitsu and Aida, Takuzo},
     journal = {Science},
     volume = {347},
     number = {6222},
     pages = {646--651},
     year = {2015},
     publisher = {American Association for the Advancement of Science},
     doi = {10.1126/science.aaa4249},
     url = {https://doi.org/10.1126/science.aaa4249},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Contrasting Behaviour of Exciplex Ensembles in the Diastereodifferentiating Paternò–Büchi Reaction of Chiral Cyanobenzoate with Naphthyl-and Phenylethenes on Direct or Charge-Transfer Excitation

   Keisuke Nagasaki, Yoshihisa Inoue, and Tadashi Mori^*

   Aust. J. Chem., 2015, 68, 1693–1699.

   Article Abs DOI Bib

   The diastereodifferentiating Paternò–Büchi reaction of chiral cyanobenzoate with 1-(1-naphthyl)-1-phenylethene was compared with those with 1,1-diphenylethene on direct and charge-transfer excitations. By desymmetrization of the donor, four diastereomeric oxetane products were formed on photolysis in excellent combined yields. Increase in donor strength induced a stronger charge-transfer interaction both in ground and excited states. Thus, the difference in diastereoselectivities with two different excitation modes (i.e. direct versus charge-transfer) became less significant with a naphthyl derivative as donor. A subtle change of donor–acceptor interaction was shown to have profound effect on the nature of the excited-state complexes and thus the product (stereo)selectivities. Despite a small temperature dependence, an Eyring-type study on the diastereoselectivities confirmed that the excited charge-transfer complex is an excited species distinct from the conventional exciplex.

   @article{nagasaki2015contrasting,
     title = {Contrasting Behaviour of Exciplex Ensembles in the Diastereodifferentiating Paternò--Büchi Reaction of Chiral Cyanobenzoate with Naphthyl-and Phenylethenes on Direct or Charge-Transfer Excitation},
     author = {Nagasaki, Keisuke and Inoue, Yoshihisa and Mori, Tadashi},
     journal = {Aust. J. Chem.},
     volume = {68},
     number = {11},
     pages = {1693--1699},
     year = {2015},
     publisher = {CSIRO Publishing},
     doi = {10.1071/ch15404},
     url = {https://doi.org/10.1071/ch15404},
     dimensions = {true},
     tab = {paper},
   }

8. Studies on Circular Dichroisms and Circular Polarized Luminescence Properties Based on Helical Structure of Helicene Derivatives

   Tadashi Mori^*

   Toyota Kenkyu Hokoku, 2015, 68, 173–174.

   Bib

   @article{mori2015studies,
     title = {Studies on Circular Dichroisms and Circular Polarized Luminescence Properties Based on Helical Structure of Helicene Derivatives},
     author = {Mori, Tadashi},
     journal = {Toyota Kenkyu Hokoku},
     volume = {68},
     pages = {173--174},
     year = {2015}
   }

2014

1. 

   Exciplex Ensemble Modulated by Excitation Mode in Intramolecular Charge-Transfer Dyad: Effects of Temperature, Solvent Polarity, and Wavelength on Photochemistry and Photophysics of Tethered Naphthalene–Dicyanoethene System

   Yoshiaki Aoki, Nobuo Matsuki, Tadashi Mori^*, Hiroshi Ikeda, and Yoshihisa Inoue^*

   Org. Lett., 2014, 16, 4888–4891.

   Article Abs DOI Bib

   Solvent, temperature, and excitation wavelength significantly affected the photochemical outcomes of a naphthalene–dicyanoethene system tethered by different number (n) of methylene groups (1–3). The effect of irradiation wavelength was almost negligible for 2a but pronounced for 3a. The temperature dependence and theoretical calculations indicated the diversity of exciplex conformations, an ensemble of which can be effectively altered by changing excitation wavelength to eventually switch the regioselectivity of photoreactions.

   @article{aoki2014exciplex,
     title = {Exciplex Ensemble Modulated by Excitation Mode in Intramolecular Charge-Transfer Dyad: Effects of Temperature, Solvent Polarity, and Wavelength on Photochemistry and Photophysics of Tethered Naphthalene--Dicyanoethene System},
     author = {Aoki, Yoshiaki and Matsuki, Nobuo and Mori, Tadashi and Ikeda, Hiroshi and Inoue, Yoshihisa},
     journal = {Org. Lett.},
     volume = {16},
     number = {18},
     pages = {4888--4891},
     year = {2014},
     publisher = {ACS Publications},
     doi = {10.1021/ol502394g},
     url = {https://doi.org/10.1021/ol502394g},
     dimensions = {true},
     tab = {paper},
   }

2. 

   C-5-Symmetric chiral corannulenes: desymmetrization of bowl inversion equilibrium via “intramolecular” hydrogen-bonding network

   Jiheong Kang, Daigo Miyajima^*, Yoshimitsu Itoh, Tadashi Mori, Hiroki Tanaka, Masahito Yamauchi, Yoshihisa Inoue, Soichiro Harada, and Takuzo Aida^*

   J. Am. Chem. Soc., 2014, 136, 10640–10644.

   Article Abs DOI Bib

   Because of a rapid conformational inversion, bowl-shaped C5-symmetric corannulenes, though geometrically chiral, have not been directly resolved into their enantiomers. However, if this inversion equilibrium can be desymmetrized, chiral corannulenes enriched in either enantiomer can be obtained. We demonstrated this possibility using pentasubstituted corannulenes 4 and 5 carrying amide-appended thioalkyl side chains. Compound 4 displays chiroptical activity in a chiral hydrocarbon such as limonene. Because compound 5 carries a chiral center in the side chains, its enantiomers 5R and 5S show chiroptical activity even in achiral solvents such as CHCl3 and methylcyclohexane. In sharp contrast, when the side chains bear no amide functionality (1 and 2R), no chiroptical activity emerges even in limonene or with a chiral center in the side chains. Detailed investigations revealed that the peripheral amide units in 4 and 5 are hydrogen-bonded only “intramolecularly” along the corannulene periphery, affording cyclic amide networks with clockwise and anticlockwise geometries. Although this networking gives rise to four stereoisomers, only two, which are enantiomeric to one another, are suggested computationally to exist in the equilibrated system. In a chiral environment (chiral solvent or side chain), their thermodynamic stabilities are certainly unequal, so the bowl-inversion equilibrium can be desymmetrized. However, this is not the case when the system contains a protic solvent that can deteriorate the hydrogen-bonding network. When the enantiomeric purity of limonene as the solvent is varied, the chiroptical activity of the corannulene core changes nonlinearly with its enantiomeric excess (majority rule).

   @article{kang2014c,
     title = {C-5-Symmetric chiral corannulenes: desymmetrization of bowl inversion equilibrium via “intramolecular” hydrogen-bonding network},
     author = {Kang, Jiheong and Miyajima, Daigo and Itoh, Yoshimitsu and Mori, Tadashi and Tanaka, Hiroki and Yamauchi, Masahito and Inoue, Yoshihisa and Harada, Soichiro and Aida, Takuzo},
     journal = {J. Am. Chem. Soc.},
     volume = {136},
     number = {30},
     pages = {10640--10644},
     year = {2014},
     publisher = {ACS Publications},
     doi = {10.1021/ja505941b},
     url = {https://doi.org/10.1021/ja505941b},
     dimensions = {true},
     tab = {paper},
   }

3. 

   ABC-Type meso-Triaryl-Substituted Subporphyrins

   Kota Yoshida, Hirotaka Mori, Takayuki Tanaka, Tadashi Mori^*, and Atsuhiro Osuka^*

   Eur. J. Org. Chem., 2014, 2014, 3997–4004.

   Article Abs DOI Bib

   ABC-Type subporphyrins 5a–5h, which bear three different meso-aryl substituents, were rationally synthesized by condensation of AB-type tripyrranes and aroyl chlorides. ABC-Type subporphyrins 5i and 5j were synthesized by Pd-catalyzed amination reaction of 4-bromophenyl subporphyrins 5e and 5h, respectively. Comparative studies on these ABC-type subporphyrins with A3-type subporphyrins and A2B-type subporphyrins revealed that substituent effects are mostly simple superpositions of individual substituents but cooperative effects are recognized for subporphyrins which bear both electron-donating and electron-withdrawing substituents. Despite extensive attempts, enantiomeric separation of B-methoxy ABC-type subporphyrins was unsuccessful, whereas B-phenylated ABC-type subporphyrins were separated to pure enantiomers. Separated enantiomers showed weak but distinct CD signals reflecting the chiral clockwise/anticlockwise arrangements of the meso-aryl substituents. These results suggest facile racemization through SN1-type heterolysis of the B–OMe bond in solution.

   @article{yoshida2014abc,
     title = {ABC-Type meso-Triaryl-Substituted Subporphyrins},
     author = {Yoshida, Kota and Mori, Hirotaka and Tanaka, Takayuki and Mori, Tadashi and Osuka, Atsuhiro},
     journal = {Eur. J. Org. Chem.},
     volume = {2014},
     number = {19},
     pages = {3997--4004},
     year = {2014},
     publisher = {Wiley Online Library},
     doi = {10.1002/ejoc.201402435},
     url = {https://doi.org/10.1002/ejoc.201402435},
     dimensions = {true},
     tab = {paper},
   }

4. 

   Ammonia-Driven Chirality Inversion and Enhancement in Enantiodifferentiating Photocyclodimerization of 2-Anthracenecarboxylate Mediated by Diguanidino-γ-cyclodextrin

   Jiabin Yao, Zhiqiang Yan, Jiecheng Ji, Wanhua Wu, Cheng Yang^*, Masaki Nishijima, Gaku Fukuhara, Tadashi Mori, and Yoshihisa Inoue^*

   J. Am. Chem. Soc., 2014, 136, 6916–6919.

   Article Abs DOI Bib

   In the supramolecular photocyclodimerization of 2-anthracenecarboxylate mediated by 6A,6D-diguanidino-γ-cyclodextrin (CD), the chiral sense and enantiomeric excess of the photoproduct were dynamic functions of temperature and cosolvent to afford the (M)-anti head-to-head cyclodimer in 64 ee in aqueous methanol at −70 °C but the antipodal (P)-isomer in 86 ee in aqueous ammonia at −85 °C, while the corresponding diamino-γ-CD host did not show such unusual photochirogenic behaviors. The ee landscape was very steep against the temperature and sign-inverted against the ammonia content to reveal the opposite temperature dependence at low and high ammonia contents, for which an altered solvent structure and/or guanidinium–carboxylate interaction mode would be responsible.

   @article{yao2014ammonia,
     title = {Ammonia-Driven Chirality Inversion and Enhancement in Enantiodifferentiating Photocyclodimerization of 2-Anthracenecarboxylate Mediated by Diguanidino-γ-cyclodextrin},
     author = {Yao, Jiabin and Yan, Zhiqiang and Ji, Jiecheng and Wu, Wanhua and Yang, Cheng and Nishijima, Masaki and Fukuhara, Gaku and Mori, Tadashi and Inoue, Yoshihisa},
     journal = {J. Am. Chem. Soc.},
     volume = {136},
     number = {19},
     pages = {6916--6919},
     year = {2014},
     publisher = {ACS Publications},
     doi = {10.1021/ja5032908},
     url = {https://doi.org/10.1021/ja5032908},
     dimensions = {true},
     tab = {paper},
   }

5. 

   Sign inversion of circularly polarized luminescence by geometry manipulation of four naphthalene units introduced into a tartaric acid scaffold

   Tomoyuki Amako, Kazuki Nakabayashi, Tadashi Mori^*, Yoshihisa Inoue, Michiya Fujiki, and Yoshitane Imai^*

   Chem. Commun., 2014, 50, 12836–12839.

   Article Abs DOI Bib

   Tethering four 1- versus 2-naphthyls to the same chiral scaffold derived from tartaric acid led to oppositely signed circularly polarized luminescence (CPL) and circular dichroism (CD) in solution, which not only reveals the decisive role of the spatial arrangement of chromophores/fluorophores in determining the chiroptical behaviors but also provides us with a versatile tool for switching the signs of CPL and CD without using the antipodal scaffold.

   @article{amako2014sign,
     title = {Sign inversion of circularly polarized luminescence by geometry manipulation of four naphthalene units introduced into a tartaric acid scaffold},
     author = {Amako, Tomoyuki and Nakabayashi, Kazuki and Mori, Tadashi and Inoue, Yoshihisa and Fujiki, Michiya and Imai, Yoshitane},
     journal = {Chem. Commun.},
     volume = {50},
     number = {85},
     pages = {12836--12839},
     year = {2014},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/c4cc04228j},
     url = {https://doi.org/10.1039/c4cc04228j},
     dimensions = {true},
     tab = {paper},
   }

6. 

   Mammalian serum albumins as a chiral mediator library for bio-supramolecular photochirogenesis: optimizing enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate

   Masaki Nishijima^*, Masato Goto, Mayu Fujikawa, Cheng Yang, Tadashi Mori, Takehiko Wada, and Yoshihisa Inoue^*

   Chem. Commun., 2014, 50, 14082–14085.

   Article Abs DOI Bib

   A simple strategy for choosing optimal bio-supramolecular mediators from the mammalian serum albumin library is proposed for bimolecular photochirogenic reactions. Thus, the enantiodifferentiating photocyclodimerization of 2-anthracencecarboxylate (AC) was optimized in chemical and optical yields, when mediated by porcine and canine serum albumins, both of which bound two AC molecules in the first productive site to give the (P)-enantiomer of syn-head-to-tail-cyclodimer in 69% yield and 89% enantiomeric excess (ee) for the former but the (M)-enantiomer in 77% yield and 97% ee for the latter.

   @article{nishijima2014mammalian,
     title = {Mammalian serum albumins as a chiral mediator library for bio-supramolecular photochirogenesis: optimizing enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate},
     author = {Nishijima, Masaki and Goto, Masato and Fujikawa, Mayu and Yang, Cheng and Mori, Tadashi and Wada, Takehiko and Inoue, Yoshihisa},
     journal = {Chem. Commun.},
     volume = {50},
     number = {91},
     pages = {14082--14085},
     year = {2014},
     publisher = {Royal Society of Chemistry},
     doi = {10.1039/c4cc04818k},
     url = {https://doi.org/10.1039/c4cc04818k},
     dimensions = {true},
     tab = {paper},
   }

7. 

   Supramolecular photocyclodimerization of 2-hydroxyanthracene with a chiral hydrogen-bonding template, cyclodextrin and serum albumin

   Gaku Fukuhara, Hiroaki Umehara, Saki Higashino, Masaki Nishijima, Cheng Yang, Tadashi Mori, Takehiko Wada, and Yoshihisa Inoue^*

   Photochem. Photobiol. Sci., 2014, 13, 162–171.

   Article Abs DOI Bib

   2-Hydroxyanthracene (HA) in its neutral form smoothly photocyclodimerized to four stereoisomeric [4 + 4]-cyclodimers, which were isolated and characterized for the first time, whereas the anionic form of HA turned out to be photochemically inert. Enantiodifferentiating photocyclodimerization of HA in the presence of a chiral hydrogen-bonding template (TKS159), γ-cyclodextrin (γ-CDx) and bovine serum albumin (BSA) was examined to afford chiral syn-head-to-tail and anti-head-to-head cyclodimers in modest enantiomeric excesses with TKS159 and γ-CDx, but practically no photocyclodimerization proceeded in the presence of BSA probably due to the ionization of HA in the binding sites.

   @article{fukuhara2014supramolecular,
     title = {Supramolecular photocyclodimerization of 2-hydroxyanthracene with a chiral hydrogen-bonding template, cyclodextrin and serum albumin},
     author = {Fukuhara, Gaku and Umehara, Hiroaki and Higashino, Saki and Nishijima, Masaki and Yang, Cheng and Mori, Tadashi and Wada, Takehiko and Inoue, Yoshihisa},
     journal = {Photochem. Photobiol. Sci.},
     volume = {13},
     number = {2},
     pages = {162--171},
     year = {2014},
     publisher = {Springer},
     doi = {10.1039/c3pp50127b},
     url = {https://doi.or10.1039/c3pp50127b},
     dimensions = {true},
     tab = {paper},
   }

8. 

   Manipulating γ-cyclodextrin-mediated photocyclodimerization of anthracenecarboxylate by wavelength, temperature, solvent and host

   Cheng Yang^*, Qian Wang, Masahito Yamauchi, Jabing Yao, Dayang Zhou, Masaki Nishijima, Gaku Fukuhara, Tadashi Mori, Yu Liu^*, and Yoshihisa Inoue^*

   Photochem. Photobiol. Sci., 2014, 13, 190–198.

   Article Abs DOI Bib

   Wavelength effects on the enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate (AC) mediated by native and modified γ-cyclodextrins (CDs) were examined in different solvents at varying temperatures to manipulate the photochirogenic outcomes beyond the thermodynamically determined re/si-enantiotopic face selectivity upon 2 : 1 complexation of AC with CD in the ground state. Indeed, the stereochemical outcomes, i.e. syn/anti, head-to-tail/head-to-head (HT/HH) and in particular enantiomer ratios, were critical functions of the irradiation wavelength, irrespective of the CD host employed. Furthermore, the wavelength effects observed strongly depended on the host structure, reaction temperature and solvent employed, for which altered stacking geometry of the complexed AC pair is thought to be responsible. By optimizing the irradiation wavelength, chiral host, temperature and solvent, an enantiomeric excess of up to 54 and −37% were achieved for chiral syn-HT and anti-HH dimers.

   @article{yang2014manipulating,
     title = {Manipulating $\gamma$-cyclodextrin-mediated photocyclodimerization of anthracenecarboxylate by wavelength, temperature, solvent and host},
     author = {Yang, Cheng and Wang, Qian and Yamauchi, Masahito and Yao, Jabing and Zhou, Dayang and Nishijima, Masaki and Fukuhara, Gaku and Mori, Tadashi and Liu, Yu and Inoue, Yoshihisa},
     journal = {Photochem. Photobiol. Sci.},
     volume = {13},
     number = {2},
     pages = {190--198},
     year = {2014},
     publisher = {Springer},
     doi = {10.1039/c3pp50255d},
     url = {https://doi.org/10.1039/c3pp50255d},
     dimensions = {true},
     tab = {paper},
   }

9. Combined experimental and theoretical investigation of chiroptical properties of helicenes and related molecules

   Tadashi Mori^*

   Symmetry, 2014, 25, 109–112.

   Bib

   @article{mori2014combined,
     title = {Combined experimental and theoretical investigation of chiroptical properties of helicenes and related molecules},
     author = {Mori, Tadashi},
     journal = {Symmetry},
     volume = {25},
     issue = {2},
     pages = {109--112},
     year = {2014},
     publisher = {Symmetry: Culture and Science}
   }