Faculty Profiles - YAMAGUCHI, Shigehiro

Papers - YAMAGUCHI, Shigehiro

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Planarized Phenyldithienylboranes: Effects of the Bridging Moieties and π‐Extension on the Photophysical Properties and Lewis Acidity Reviewed

Mika Sakai, Masayoshi Mori, Masato Hirai, Naoki Ando, Shigehiro Yamaguchi

Chemistry – A European Journal Vol. 28 ( 38 ) page： e202200728 2022.7

Fluorescent Organic pi-Radicals Stabilized with Boron: Featuring a SOMO-LUMO Electronic Transition Reviewed

Masato Ito, Shusuke Shirai, Yongfa Xie, Tomokatsu Kushida, Naoki Ando, Hiroki Soutome, Kazuhiro J. Fujimoto, Takeshi Yanai, Kenichi Tabata, Yasuo Miyata, Hiroshi Kita, Shigehiro Yamaguchi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 61 ( 25 ) page： e202201965 2022.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

We report on the fluorescence properties of a new class of emissive and stable pi-radicals that contain a boron atom at a position distant from the radical center. A fully planarized derivative exhibited an intense red fluorescence with high fluorescence quantum yields (Phi(F) > 0.67) even in polar solvents. To elucidate the origin of this phenomenon, we synthesized another boron-stabilized radical that contains a bulky aryl group on the boron atom. A comparison of these derivatives, as well as with conventional donor-rr-acceptor (D-pi-A)-type emissive pi-radicals, unveiled several characteristic features in their photophysical properties. A theoretical analysis revealed that the SOMO-LUMO electronic transition generates an emissive D-1 state. Unlike conventional D-pi-A-type pi-radicals, this state does not undergo significant structural relaxation. The boron-stabilized pi-radicals demonstrated promising potential for organic light-emitting diodes as an emitting material.

DOI： 10.1002/anie.202201965

Web of Science

PubMed

A negative-solvatochromic fluorescent probe for visualizing intracellular distributions of fatty acid metabolites Reviewed International coauthorship

Keiji Kajiwara, Hiroshi Osaki, Steffen Greßies, Keiko Kuwata, Ju Hyun Kim, Tobias Gensch, Yoshikatsu Sato, Frank Glorius, Shigehiro Yamaguchi, Masayasu Taki

Nature Communications Vol. 13 ( 1 ) page： 2533 2022.5

Fully fused boron-doped polycyclic aromatic hydrocarbons: their synthesis, structure-property relationships, and self-assembly behavior in aqueous media Reviewed

Hiroki Narita, Heekyoung Choi, Masato Ito, Naoki Ando, Soichiro Ogi, Shigehiro Yamaguchi

CHEMICAL SCIENCE Vol. 13 ( 5 ) page： 1484 - 1491 2022.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

Planarized triarylboranes are attracting increasing attention not only as models of boron-doped graphenes, but also as promising materials for organic optoelectronics. In particular, polycyclic aromatic hydrocarbon (PAH) skeletons with embedded boron atom(s) in the inner positions are of importance in light of their high chemical stability and pi-stacking ability derived from their planar geometries. Herein, we disclose a robust synthesis of such fully fused boron-doped PAHs and their self-assembly behavior in aqueous media to explore their potential utility in biological applications. The synthesis using in situ-generated planar diarylboranes as a key precursor afforded a series of fully fused boron-doped PAHs, even including an amphiphilic derivative with hydrophilic side chains. These compounds exhibited red emission in solution, and slight structural modification resulted in increased fluorescence brightness. While these compounds showed relatively low Lewis acidity compared to their partially ring-fused counterparts, their Lewis acidities were slightly increased in polar solvents compared to those in nonpolar solvents. In addition, their B-N Lewis acid-base adducts, even those with a strong, charge-neutral Lewis base such as N,N-dimethylaminopyridine (DMAP), exhibited photo-dissociation behavior in the excited state. The amphiphilic derivative showed significant spectral changes with increased water content in DMSO/H2O mixed media and formed sheet-like aggregates. The disassembly and assembly processes of the aggregates were externally controlled by the addition of DMAP and an acid, accompanied by a change in the fluorescence intensity.

DOI： 10.1039/d1sc06710a

Web of Science

PubMed

A Supramolecular Polymer Constituted of Antiaromatic Ni II Norcorroles Reviewed

Shusaku Ukai, Aiko Takamatsu, Masaki Nobuoka, Yusuke Tsutsui, Norihito Fukui, Soichiro Ogi, Shu Seki, Shigehiro Yamaguchi, Hiroshi Shinokubo

Angewandte Chemie International Edition Vol. 61 ( 6 ) page： e202114230 2022.2

Photobase-Driven Excited-State Intramolecular Proton Transfer (ESIPT) in a Strapped π-Electron System Reviewed

Suzuki, N; Kubota, T; Ando, N; Yamaguchi, S

CHEMISTRY-A EUROPEAN JOURNAL Vol. 28 ( 4 ) page： e202103584 2022.1

Pro-tumoral behavior of omental adipocyte-derived fibroblasts in tumor microenvironment at the metastatic site of ovarian cancer Reviewed

Iyoshi, S; Yoshihara, M; Nakamura, K; Sugiyama, M; Koya, Y; Kitami, K; Uno, K; Mogi, K; Tano, S; Tomita, H; Kajiwara, K; Taki, M; Yamaguchi, S; Nawa, A; Kajiyama, H

INTERNATIONAL JOURNAL OF CANCER Vol. 149 ( 11 ) page： 1961 - 1972 2021.12

Electron-Deficient Heteroacenes that Contain Two Boron Atoms: Near-Infrared Fluorescence Based on a Push-Pull Effect** Reviewed

Masato Ito, Mika Sakai, Naoki Ando, Shigehiro Yamaguchi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 60 ( 40 ) page： 21853 - 21859 2021.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Electron-deficient heteroacenes that contain two tricoordinate boron atoms in their acene skeletons and planarized phenyl ether moieties at their periphery were synthesized via the borylation of silicon-bridged precursors. X-ray crystallographic analysis revealed quinoidal structures, which give rise to two-step reversible redox processes for both the reduction and oxidation. These compounds exhibit intense absorption and sharp fluorescence bands with vibronic structures in the near-infrared (NIR) region. These properties originate from the push-pull effect along the long axis of the molecule derived from the electron-donating ether moieties and the electron-accepting boron moieties. Of particular note is the NIR emission of the thienothiophene-centered heteroacene, which has a maximum at 952 nm with a narrow band width of 309 cm(-1) in cyclohexane. A Franck-Condon analysis revealed the crucial role of the sterically less-hindered thienothiophene spacer in achieving this sharp emission band.

DOI： 10.1002/anie.202106642

Web of Science

PubMed

Regio- and Stereoselective 1,2-Carboboration of Ynamides with Aryldichloroboranes Reviewed International coauthorship

You, C; Sakai, M; Daniliuc, CG; Bergander, K; Yamaguchi, S; Studer, A

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 60 ( 40 ) page： 21697 - 21701 2021.9

Boron-Doped Polycyclic π-Electron Systems with an Antiaromatic Borole Substructure That Forms Photoresponsive B–P Lewis Adducts Reviewed International coauthorship

Naoki Ando, Takuya Yamada, Hiroki Narita, Niels N. Oehlmann, Matthias Wagner, Shigehiro Yamaguchi

Journal of the American Chemical Society Vol. 143 ( 26 ) page： 9944 - 9951 2021.7

Late-stage functionalisation of alkyne-modified phospha-xanthene dyes: lysosomal imaging using an off–on–off type of pH probe Reviewed

Hiroaki Ogasawara, Yoshiki Tanaka, Masayasu Taki, Shigehiro Yamaguchi

Chemical Science Vol. 12 ( 22 ) page： 7902 - 7907 2021.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Royal Society of Chemistry (RSC)

<p>A series of NIR-emissive phospha-xanthene dyes bearing an ethynyl group are reported. The late-stage functionalisation of the NIR dyes enables creation of multi-functionalised fluorescent probes that can be designed to target organelles of interest.</p>

DOI： 10.1039/d1sc01705e

Web of Science

PubMed

Donor-acceptor-acceptor-type near-infrared fluorophores that contain dithienophosphole oxide and boryl groups: effect of the boryl group on the nonradiative decay dagger Reviewed

Yoshiaki Sugihara, Naoto Inai, Masayasu Taki, Thomas Baumgartner, Ryosuke Kawakami, Takashi Saitou, Takeshi Imamura, Takeshi Yanai, Shigehiro Yamaguchi

CHEMICAL SCIENCE Vol. 12 ( 18 ) page： 6333 - 6341 2021.5

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

The use of donor-pi-acceptor (D-pi-A) skeletons is an effective strategy for the design of fluorophores with red-shifted emission. In particular, the use of amino and boryl moieties as the electron-donating and -accepting groups, respectively, can produce dyes that exhibit high fluorescence and solvatochromism. Herein, we introduce a dithienophosphole P-oxide scaffold as an acceptor-spacer to produce a boryl- and amino-substituted donor-acceptor-acceptor (D-A-A) pi-system. The thus obtained fluorophores exhibit emission in the near-infrared (NIR) region, while maintaining high fluorescence quantum yields even in polar solvents (e.g. lambda(em) = 704 nm and phi(F) = 0.69 in CH3CN). A comparison of these compounds with their formyl- or cyano-substituted counterparts demonstrated the importance of the boryl group for generating intense emission. The differences among these electron-accepting substituents were examined in detail using theoretical calculations, which revealed the crucial role of the boryl group in lowering the nonradiative decay rate constant by decreasing the non-adiabatic coupling in the internal conversion process. The D-A-A framework was further fine-tuned to improve the photostability. One of these D-A-A dyes was successfully used in bioimaging to visualize the blood vessels of Japanese medaka larvae and mouse brain.

DOI： 10.1039/d1sc00827g

Web of Science

PubMed

Dual Trapping of a Metastable Planarized Triarylborane pi-System Based on Folding and Lewis Acid-Base Complexation for Seeded Polymerization Reviewed

Heekyoung Choi, Soichiro Ogi, Naoki Ando, Shigehiro Yamaguchi

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 143 ( 7 ) page： 2953 - 2961 2021.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

We report the kinetically controlled supramolecular polymerization of boron-containing p-conjugated molecules, which was enabled by a seeding method based on dual trapping of a metastable state by synergistic intramolecular hydrogen bonding and Lewis acid-based complexation. Planarized triarylborane-based 1, which bears a diamide chain with chiral alkyl groups, was synthesized. Upon cooling, the solution of monomer 1 afforded a supramolecular polymerization in a cooperative manner to form helical supramolecular nanostructures with intense J-type aggregate emission. In the presence of pyridine, the triarylborane moiety formed a Lewis acid-base complex, which enhances the stabilization of the metastable monomeric state. An assembly incompetent structure with a folded diamide chain conformation and a pyridine moiety axially coordinated to the boron atom is responsible for slowing the spontaneous aggregation. The seeding method was successfully applied to the solution to produce homogeneous nanofibers even at a high (millimolar-level) concentration. This unprecedented kinetic control via dual trapping provides an effective method to achieve seed-initiated polymerization under concentrated conditions.

DOI： 10.1021/jacs.0c13353

Web of Science

PubMed

Twofold C-H Activation Enables Synthesis of a Diazacoronene-Type Fluorophore with Near Infrared Emission Through Isosteric Replacement Reviewed International coauthorship

Steffen Gressies, Masato Ito, Mika Sakai, Hiroshi Osaki, Ju Hyun Kim, Tobias Gensch, Constantin Daniliuc, Naoki Ando, Shigehiro Yamaguchi, Frank Glorius

CHEMISTRY-A EUROPEAN JOURNAL Vol. 27 ( 8 ) page： 2753 - 2759 2021.2

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

The synthesis and photophysical properties of a soluble amide-embedded coronene is reported. The key step in this synthesis is the twofold C-H activation of diazaperylene by a rhodium(III)Cp* catalyst. This unprecedented structural motif shows intense fluorescence in the near infrared region with a small Stokes shift and a distinct vibronic structure, which exhibits a slight extent of negative solvatochromism. Comparison of this compound with some relevant compounds revealed the importance of the amide incorporation in the peripheral concave region including an angular position to retain high aromaticity reflecting that of parent coronene. Treatment of this compound with Lewis acid B(C6F5)(3) formed a bis-adduct, which exhibited enhanced aromaticity as a consequence of the increased double bond character of the amide C-N bonds.

DOI： 10.1002/chem.202004080

Web of Science

PubMed

Fused Thiophene-S,S-dioxide-Based Super-Photostable Fluorescent Marker for Lipid Droplets Reviewed

Masayasu Taki, Keiji Kajiwara, Eriko Yamaguchi, Yoshikatsu Sato, Shigehiro Yamaguchi

ACS MATERIALS LETTERS Vol. 3 ( 1 ) page： 42 - 49 2021.1

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Lipid droplets (LDs) are essential organelles in most eukaryotes, and tracking intracellular LD dynamics using synthetic small molecules is crucial for biological studies. However, only a limited number of fluorescent markers that satisfy all requirements, such as the selective staining of LDs, high photostability, and sufficient biocompatibility, have been developed. Herein, we report a series of donor-p-acceptor dyes based on the thiophene-containing fused polycyclic scaffold [1]benzothieno[3,2-b][1]benzothiophene (BTBT), in which either or both thiophene rings are oxidized into thiophene-S,S-dioxide to form an electron-accepting building block. Among these dyes, LAQ1 satisfied all the aforementioned requirements and allowed us to capture ultrasmall LDs on the endoplasmic reticulum (ER) membrane by stimulation emission depletion (STED) microscopy with a super-resolution below the diffraction limit of light. Moreover, the extremely high photostability of LAQ1 enabled recording the lipolysis of LDs and the concomitant lipogenesis, as well as long-term trajectory analysis of micro-LDs at the single-particle level in living cells.

DOI： 10.1021/acsmaterialslett.0c00451

Web of Science

Phosphole P-Oxide-Containing pi-Electron Materials: Synthesis and Applications in Fluorescence Imaging

Yamaguchi Shigehiro, Fukazawa Aiko, Taki Masayasu

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN Vol. 75 ( 11 ) page： 1179 - 1187 2017.11

Color-tunable fluorescent nanoparticles encapsulating trialkylsilyl-substituted pyrene liquids

Taki Masayasu, Azeyanagi Saki, Hayashi Kenzo, Yamaguchi Shigehiro

JOURNAL OF MATERIALS CHEMISTRY C Vol. 5 ( 8 ) page： 2142 - 2148 2017.2

A strap strategy for construction of an excited-state intramolecular proton transfer (ESIPT) system with dual fluorescence.

Suzuki N, Fukazawa A, Nagura K, Saito S, Kitoh-Nishioka H, Yokogawa D, Irle S, Yamaguchi S

Angewandte Chemie (International ed. in English) Vol. 53 ( 31 ) page： 8231 - 5 2014.7

Regioselective Unsymmetrical Tetraallylation of C-60 through Palladium Catalysis

Nambo Masakazu, Wakamiya Atsushi, Yamaguchi Shigehiro, Itami Kenichiro

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 131 ( 42 ) page： 15112 - + 2009.10

Design and synthesis of boron-containing functional pi-electron materials

Wakamiya Atsushi, Yamaguchi Shigehiro

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN Vol. 66 ( 9 ) page： 858 - 868 2008.9

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Papers - YAMAGUCHI, Shigehiro