Faculty Profiles - YAMAGUCHI, Shigehiro

Papers - YAMAGUCHI, Shigehiro

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Tetraaryl-tetradecahydroporphyrazins: Novel Porphyrin Derivatives Featuring a Cyclic Benzene Ring Tetramer

S. Janich, R. Froehlich, A. Wakamiya, S. Yamaguchi, and E.-U. Wuerthwein

Chem. Eur. J. Vol. 15 page： 10457-10463 2009

Highly Emissive Diborylphenylene-Containing Bis(phenylethynyl)benzenes: Structure–Photophysical Property Correlations and Fluoride Ion Sen

C.-H. Zhao, E. Sakuda, A. Wakamiya, and S. Yamaguchi

Chem. Eur. J. Vol. 15 page： 10603-10612 2009

*A B-B Bond-Containing Polycyclic π-Electron System: Dithieno-1,2-dihydro-1,2-diborin and Its Dianion Reviewed Open Access

A. Wakamiya, K. Mori, T. Araki, and S. Yamaguchi

J. Am. Chem. Soc. Vol. 131 page： 10850-10851 2009

Ladder pi-Conjugated Materials Containing Main Group Elements Open Access

A. Fukazawa, S. Yamaguchi

Chem. Asian J. Vol. 4 page： 1386-1400 2009

Oxidation of End-Capped Pentathienoacenes and Characterization of Their Radical Cations Open Access

R. M. Osuna, M. C. R. Delgado, V. V. Hernández, J. T. L. Navarrete, B. Vercelli, G. Zotti, J. J. Novoa, Y. Suzuki, S. Yamaguchi, J. T. Henssler, A. J. Matzger

Chem. Eur. J Vol. 15 page： 12346-12361 2009

Benzo[b]phosphole-Containing π-Electron Systems: Synthesis Based on an Intramolecular trans-Halophosphanylation and Some Insights into Their Properties

A. Fukazawa, Y. Ichihashi, Y. Kosaka, and S. Yamaguchi

Chem. Asian J. Vol. 4 page： 1729-1740 2009

Regioselective Unsymmetrical Tetraallylation of C60 through Palladium Catalysis Open Access

M. Nambo, A. Wakamiya, S. Yamaguchi, and K. Itami

J. Am. Chem. Soc. Vol. 131 page： 15112-15113 2009

Intense solid-state blue emission with a small Stokes' shift: pi-stacking protection of the diphenylanthracene skeleton

Azusa Iida, Shigehiro Yamaguchi

CHEMICAL COMMUNICATIONS ( 21 ) page： 3002 - 3004 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

Intense blue emissions with a small Stokes' shift both in solution and in the solid state were attained by introducing (pentafluorophenyl) dimethylsilyl groups to a 9,10-diphenylanthracene skeleton as the pi-stacking tethers.

DOI： 10.1039/b901794a

Web of Science

PubMed

Benzo[b]phosphole-Containing pi-Electron Systems: Synthesis Based on an Intramolecular trans-Halophosphanylation and Some Insights into Their Properties

Aiko Fukazawa, Yasunori Ichihashi, Youhei Kosaka, Shigehiro Yamaguchi

CHEMISTRY-AN ASIAN JOURNAL Vol. 4 ( 11 ) page： 1729 - 1740 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

The intramolecular trans-halophosphanylation of 2-(aminophosphanyl)phenylacetylenes mediated by PBr3 followed by the oxidation with H2O2 produces 3-bromobenzo[b]phosphole oxide derivatives. This cyclization is also used for the synthesis of a 3-iodo derivative by conducting the reaction in the presence of LiI. Based on this synthetic method, various benzophosphole-containing pi-conjugated compounds, including a phosphoryl and methylene-bridged stilbene 10, 2,3,6,7-tetraphenylbenzo[1,2-b:4,5-b']diphosphole-P,P'-dioxides 11, and their phosphine sulfide derivatives 12, are synthesized. The study of the structure-property relationships in a series of the bridged stilbenes, including a bis(methylene)-bridged stilbene 10, and a bis-(phosphoryl)-bridged stilbene, reveals that as the contribution of the phosphoryl groups increased, the absorption and emission maxima substantially shift to longer wavelengths. The intrinsic substituent effects of the phosphoryl group in this skeleton are to decrease the oscillator strength of the electronic transition and thus decrease the radiative decay rate constants from the singlet excited state. Nevertheless, these compounds maintain high fluorescence quantum yields (Phi(F) > 0.8) owing to the significantly retarded non-radiative decay process. In the study of the benzodiphosphole derivatives 11 and 12, their cyclic voltammetry revealed that both of the phosphoryl and phosphine sulfide derivatives have low reduction potentials (-1.7 to -1.8 V vs ferrocene/ferrocenium couple) with the high reversibility of the redox waves. These compounds also showed high thermal stabilities with the high glass transition temperatures of 147-159 degrees C, indicative of their potential utilities as amorphous materials.

DOI： 10.1002/asia.200900303

Web of Science

PubMed

5-Aryl-3,3,4,4-tetramethyl-3,4-dihydro-3H-pyrrol-2-imines

S. Janich, R. Froehlich, A. Wilken, J. von Zamory, A. Wakamiya, S. Yamaguchi, E.-U. Wuerthwein

Eur. J. Org. Chem. page： 2077-2087 2009

Highly Emissive Diborylphenylene-Containing Bis(phenylethynyl)benzenes: Structure-Photophysical Property Correlations and Fluoride Ion Sensing

Cui-Hua Zhao, Eri Sakuda, Atsushi Wakamiya, Shigehiro Yamaguchi

CHEMISTRY-A EUROPEAN JOURNAL Vol. 15 ( 40 ) page： 10603 - 10612 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

A series of 2,5-bis(dimesitylboryl)-1,4-bis(arylethynyl)benzenes 1-6 that contain various p-substituents on the terminal benzene rings, including NPh2 (1), OMe (2), Me (3), H (4), CF3 (5), and CN (6) groups, were synthesized, and the effects of the p-substituents on the absorption and fluorescence properties were investigated both in solution and in the solid state. Linear relationships were obtained not only between the Hammett sigma(+)(p) constants of the p-substituents and the absorption and fluorescence maxima, quantum yields, and excited-state dynamics parameters in solution, but also between the sigma(+)(p) constants and the fluorescence quantum yields in the solid state. An important finding extracted from these results is that the suppressed fluorescence quenching in the solid state is a common feature for the present laterally boryl-substituted pi-conjugated skeletons. Hence, the diborylphenylene can serve as a useful core unit to develop highly emissive organic solids. In fact, most of the derivatives showed more intense emission in the solid state than in solution. In addition to these studies, the titration experiment of 1 by the addition of nBu(4)NF was conducted, which showed the stepwise bindings of two fluoride ions with high association constants as well as a drastic change in the fluorescence spectra, while constantly maintaining high quantum yields (0.61-0.76), irrespective of the binding modes. This result also demonstrated the potential utility of the present molecules as an efficient fluorescent fluoride ion sensor.

DOI： 10.1002/chem.200900864

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PubMed

Oxidation of End-Capped Pentathienoacenes and Characterization of Their Radical Cations Open Access

Reyes Malave Osuna, M. Carmen Ruiz Delgado, Victor Hernandez, Juan T. Lopez Navarrete, Barbara Vercelli, Gianni Zotti, Juan J. Novoa, Yoshitake Suzuki, Shigehiro Yamaguchi, John T. Henssler, Adam J. Matzger

CHEMISTRY-A EUROPEAN JOURNAL Vol. 15 ( 45 ) page： 12346 - 12361 2009

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

A detailed investigation of the optical and electrochemical properties of two pentathienoacene derivatives, 2,6-bis(trimethylsilyl)-alpha-pentathienoacene (TMS-T5-TMS) and 2,6-bis(triisopropylsilyl)-alpha-pentathienoacene (TIPS-T5-TIPS), as the neutral and oxidized species was performed in the temperature range of 80-300 K. The experimental solution UV/Vis and solid-state Raman spectra were interpreted by using time-dependent DFT and DFT quantum chemical calculations at the B3LYP/6-31G** level. Bond lengths, HOMO-LUMO positions, and charge distribution were also predicted by computational methods for both the neutral and oxidized states of each thienoacene. As evidenced by ESR and spectroelectrochemical data, upon oxidation the pentathienoacene derivative with the less sterically hindering trimethylsilyl solubilizing groups, TMS-T5-TMS, undergoes pi dimerization to form [TMS-T5-TMS](2)(2+). In contrast, TIPS-T5-TIPS, with the more bulky triisopropylsilyl solubilizing groups, was oxidized to the radical cation but dimerization was prevented due to steric interactions. These experimental observations are supported by DFT calculations, which were used to investigate [TMS-T5-TMS](2)(2+) and [TIPS-T5-TIPS](2)(2+) pi dimers in the solid state and in solution. The redox potentials and absorption peak locations corresponding to the radical cations and pi dimer of TMS-T5-TMS were identified experimentally.

DOI： 10.1002/chem.200900246

Web of Science

PubMed

Ladder pi-Conjugated Materials Containing Main-Group Elements Open Access

Aiko Fukazawa, Shigehiro Yamaguchi

CHEMISTRY-AN ASIAN JOURNAL Vol. 4 ( 9 ) page： 1386 - 1400 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Ladder pi-conjugated compounds, which have fully ring-fused polycyclic skeletons, are an important class of materials possessing significant potentials for application in organic electronics. The incorporation of main-group elements, such as B, Si P, S, and Se, into the ladder skeletons as bridging moieties is a powerful strategy to endow unusual electronic structures as well as suitable molecular arrangements in the solid state, giving rise to attractive photophysical and electronic properties. Recent efforts have produced a number of fascinating ladder materials, some of which indeed showed high performance as light-emitting materials and charge carrier transporting materials. This Focus Review is an overview of the progress in this chemistry, focusing on several important pi-conjugated skeletons.

DOI： 10.1002/asia.200900179

Web of Science

PubMed

Regioselective Unsymmetrical Tetraallylation of C60 through Palladium Catalysis

M. Nambo, A. Wakamiya, S. Yamaguchi, K. Itami

J. Am. Chem. Soc. Vol. 131 page： 15112-15113 2009

Tetraaryl Tetradecahydroporphyrazins: Novel Porphyrin Derivatives Featuring a Cyclic Benzene-Ring Tetramer

Simon Janich, Roland Froehlich, Atsushi Wakamiya, Shigehiro Yamaguchi, Ernst-Ulrich Wuerthwein

CHEMISTRY-A EUROPEAN JOURNAL Vol. 15 ( 40 ) page： 10457 - 10463 2009

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

Treatment of tetramethylsuccinonitrile 1 with aryl lithium compounds and subsequent quenching with chlorotrimethylsilane yields 5-aryl-3,3,4,4-tetramethyl-N-(trimethylsilyl)-3,4-dihydropyrrol-2-imines 2a-c in 49-71% yield. Attempts to crystallise 2a-c in the presence of wet air yielded the tetraaryl tetradecahydroporphyrazins 3a-c in yields of 4-84% as single diastereomers. X-ray diffraction studies of 3b and c showed that only the isomer with four aryl substituents pointing in the same direction was formed. The resulting four-bladed pinwheel-like structures were characterised by four intramolecular aromatic interactions, in which each phenyl ring points with its edge towards the centre of a neighbouring phenyl moiety, resembling the arrangement of benzene molecules in T-shaped dimers. Temperature-dependent NMR spectra give insight into the dynamic properties of the aryl substituents. Quantum chemical calculations that included dispersion corrections indicated the importance of aryl-aryl interactions for the diastereoselectivity of the reaction and for the structural properties of the single isomers observed.

DOI： 10.1002/chem.200901187

Web of Science

PubMed

Synthesis and Electronic Spectra of Disilatriptycene Oligomers: Evidence for Electronic Delocalization along the One-Dimensional Arrangement of Bridge-Head Disilanes

Shohei Sase, Yoen-Seok Cho, Atsushi Kawachi, Atsushi Wakamiya, Shigehiro Yamaguchi, Hayato Tsuji, Kohei Tamao

ORGANOMETALLICS Vol. 27 ( 21 ) page： 5441 - 5445 2008.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Reductive coupling of a 9,10-dibromo-9,10-disilatriptycene derivative followed by treatment with chlorotrimethylsilane (TMSCI) affords a series of TMS-capped 9, 10-disilatriptycene oligomers DSiT[n]. Each isomer, up to the pentamer (n = 5), can be separated using recycling gel permeation chromatography. The X-ray structural analysis of DSiT[2] shows that the six silicon atoms are linearly aligned in a rigid array structure. While the ultraviolet (UV) absorption maximum remains constant at 230 nm, irrespective of the chain length, the magnetic circular dichroism (MCD) spectra exhibit a red shift band near 245 nm, and the emission maximum steadily shifts from 319 to 337 nm as the number of silicon atom increases. These spectra indicate the occurrence of electronic delocalization along the one-dimensional arrangement of bridge-head disilane moieties.

DOI： 10.1021/om701283e

Web of Science

Red-emissive Polyphenylated BODIPY Derivatives: Effect of Peripheral Phenyl Groups on the Photophysical and Electrochemical Properties

Atsushi Wakamiya, Naoya Sugita, Shigehiro Yamaguchi

CHEMISTRY LETTERS Vol. 37 ( 10 ) page： 1094 - 1095 2008.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：CHEMICAL SOC JAPAN

A series of red-emissive BODIPY derivatives 2-4 having five to seven phenyl groups on their periphery were synthesized., and their photophysical and electrochemical properties were investigated. While the 8-phenyl-substituted derivatives only have moderate fluorescence quantum yields in solution, they can show intense red fluorescence in the PMMA films. The peripheral phenyl groups also affect the redox reversibility in cyclic voltammetry.

DOI： 10.1246/cl.2008.1094

Web of Science

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

Atsushi Wakamiya, Shigehiro Yamaguchi

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

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SOC SYNTHETIC ORGANIC CHEM JPN

Utilization of boron, a group 13 element, as a key element for developing new functional electronic and optoelectronic materials is an important direction in the organoboron chemistry. Boron has several characteristic features, such as trigonal planar geometry for trivalent boron compounds, high Lewis acidity, and effective orbital interaction with pi-conjugated frameworks through the vacant p-orbital (i.e., p(pi)-pi* conjugation). Exploiting these features of the boron element for molecular designs allows us to create sophisticated pi-electron materials having attractive photophysical and electronic properties. We here present some progress in our chemistry, including B,B',B"-trianthrylborazine (B3N3)-based molecular bundles, boryl-substituted thienylthiazole pi-electron systems with intramolecular B-N coordination, borole- and dibenzoborole-based pi-conjugated compounds, and boryl-substituted emissive organic solids.

DOI： 10.5059/yukigoseikyokaishi.66.858

Web of Science

Scopus

Electronic modulation of fused oliglothiophenes by chemical oxidation

Yoshitake Suzuki, Toshihiro Okamoto, Atsushi Wakamiya, Shigehiro Yamaguchi

ORGANIC LETTERS Vol. 10 ( 16 ) page： 3393 - 3396 2008.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

The reaction of pentathienoacene (f-5T) with mCPBA produced a series of oxidized derivatives containing one or two thiophene-S,S-dioxide rings. The regioselectivity of the oxidation reflects the aromaticity of each thiophene ring in the f-5T skeleton, and the extent of the oxidation significantly affects the fluorescence and redox properties.

DOI： 10.1021/ol801136k

Web of Science

PubMed

Highly electron-donating 3,3 '-diaryl-1,1 '-bi(isobenzofuran)s synthesized by photochemical exocyclic [2+2+2] cycloaddition

Hongyu Zhang, Atsushi Wakamiya, Shigehiro Yamaguchi

ORGANIC LETTERS Vol. 10 ( 16 ) page： 3591 - 3594 2008.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Facile photochemical exocyclic [2 + 2 + 2] cycloaddition produced a series of electron-donating 1,1'-bi(isobenzofuran)s having various aryl groups at the 3,3' positions. The 1,1'-bi(isobenzofuran) skeleton with a highly coplanar structure is a useful building unit to construct the narrow bandgap pi-conjugated systems with low oxidation potentials.

DOI： 10.1021/ol801358c

Web of Science

PubMed

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Papers - YAMAGUCHI, Shigehiro