Mitsuhiko Shionoya

The University of Tokyo, Tōkyō, Japan

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Publications (186)1100.15 Total impact

  • Shohei Tashiro · Mihoko Yamada · Mitsuhiko Shionoya
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    ABSTRACT: The cleavage of CC bonds in π-conjugated systems is an important method for controlling their shape and coplanarity. An efficient way for the cleavage of an aromatic CC bond in a typical buckybowl corannulene skeleton is reported. The reaction of 2-pyridylcorannulene with a catalytic amount of IrCl3⋅n H2O in ethylene glycol at 250 °C resulted in a structural transformation from the curved corannulene skeleton to a strain-free flat benzo[ghi]fluoranthene skeleton through a site-selective CC cleavage reaction. This cleavage reaction was found to be driven by both the coordination of the 2-pyridyl substituent to iridium and the relief of strain in the curved corannulene skeleton. This finding should facilitate the design of carbon nanomaterials based on CC bond cleavage reactions.
    Angewandte Chemie 03/2015; 127(18). DOI:10.1002/ange.201500819
  • Shohei Tashiro · Mihoko Yamada · Mitsuhiko Shionoya
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    ABSTRACT: The cleavage of CC bonds in π-conjugated systems is an important method for controlling their shape and coplanarity. An efficient way for the cleavage of an aromatic CC bond in a typical buckybowl corannulene skeleton is reported. The reaction of 2-pyridylcorannulene with a catalytic amount of IrCl3 ⋅n H2 O in ethylene glycol at 250 °C resulted in a structural transformation from the curved corannulene skeleton to a strain-free flat benzo[ghi]fluoranthene skeleton through a site-selective CC cleavage reaction. This cleavage reaction was found to be driven by both the coordination of the 2-pyridyl substituent to iridium and the relief of strain in the curved corannulene skeleton. This finding should facilitate the design of carbon nanomaterials based on CC bond cleavage reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Angewandte Chemie International Edition in English 03/2015; 54(18). DOI:10.1002/anie.201500819 · 13.45 Impact Factor
  • Kenichiro Omoto · Shohei Tashiro · Masumi Kuritani · Mitsuhiko Shionoya
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    ABSTRACT: A macrocyclic host molecule possessing a nano-cavity with two AgI centers for guest binding and four anthracene walls has been developed. This dimetal-macrocycle forms stable inclusion complexes with ditopic aromatic guest molecules, [2.2]paracyclophane and ferrocene, in solution and/or in the solid state through Ag-π interactions within the nano-cavity. The binding constants for the inclusion complexes were found to range roughly from 104 to 109 M-1. Electrochemical measurement revealed that the oxidized form of the included cationic ferrocene was less stabilized due to the direct binding to the cationic two AgI centers.
    Journal of the American Chemical Society 12/2014; 136(52). DOI:10.1021/ja5106249 · 11.44 Impact Factor
  • Ryou Kubota · Shohei Tashiro · Motoo Shiro · Mitsuhiko Shionoya
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    ABSTRACT: Molecular adsorption is a fundamental phenomenon in porous materials and is usually characterized by the efficiency and selectivity of molecular separations and reactions. However, for functional porous materials, analysis of the dynamic behaviour of molecular adsorbents is a major challenge. Here, we use in situ single-crystal X-ray diffraction to analyse multi-step molecular adsorption in a crystalline nanochannel of a metal-macrocycle framework. The pore surface of the metal-macrocycle framework crystal contains five different enantiomerically paired binding pockets, to which the adsorption of a (1R)-1-(3-chlorophenyl)ethanol solution was monitored with time. The resulting X-ray snapshot analyses suggest that the guest adsorption process takes a two-step pathway before equilibrium, in which the guest molecule is temporarily trapped by a neighbouring binding site. This demonstrates the potential for using X-ray analyses to visualize a transient state during a non-covalent self-assembly process.
    Nature Chemistry 10/2014; 6(10):913-8. DOI:10.1038/nchem.2044 · 23.30 Impact Factor
  • Shohei Tashiro · Mitsuhiko Shionoya
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    ABSTRACT: Porous crystals such as metal-organic framework (MOF), porous coordination polymer (PCP), and porous organic crystals have shown promise as solid materials in terms of their great potentials for catalysis, separation and refinement techniques, environmental protection, nanoengineering, and pharmaceutical applications. Here we discuss cavity-assembled porous solids (CAPSs) formed as the result of self-assembly of macrocycles or cage compounds possessing well-defined binding cavities for guest molecules. In addition to conventional macrocycles such as cyclodextrin, crown ether, cucurbituril, calixarene, cyclotriveratrylene, pillararene, and organic cages, we have recently reported a novel crystalline nanochannel (metal-macrocycle framework: MMF) composed of macrocyclic trinuclear Pd-II complexes with tris(o-phenylenediamine)cyclophane. This account focuses on how cavities with guest-binding capability assemble to form porous structures taking recent examples.
    ChemInform 09/2014; 45(35). DOI:10.1002/chin.201435265
  • Mihoko Yamada · Kei Ohkubo · Mitsuhiko Shionoya · Shunichi Fukuzumi
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    ABSTRACT: A charge-transfer (CT) complex was formed between corannulene (C20H10) and lithium ion-encapsulated [60]fullerene (Li+@C60) with the binding constant KG = 1.9 × 10 M-1 by concave-convex π-π CT interactions in benzonitrile at 298 K, exhibiting a broad CT absorption extended to the NIR region. Femotosecond laser excitation of the C20H10/Li+@C60 CT complex resulted in the singlet charge-separated (CS) state, 1(C20H10•+/Li+@C60•-), which decayed with the lifetime of 1.4 ns. Nanosecond laser excitation of Li+@C60 resulted in intermolecular electron transfer (ET) from C20H10 to the triplet excited state of Li+@C60 [3(Li+@C60)*] to produce the triplet CS state 3(C20H10•+/Li+@C60•-). The distance between two electron spins in the triplet CS state was estimated to be 10 Å from the zero-field splitting pattern observed by EPR measurements at 4 K. The triplet CS state decayed to the ground state via intramolecular back electron transfer (BET) in the CS state. The CS lifetime was determined to be 240 μs in benzonitrile at 298 K. The temperature dependence of the rate constant of BET afforded the reorganization energy (λ = 1.04 eV) and the electronic coupling term (V = 0.0080 cm-1). The long lifetime of CS state results from the spin-forbidden BET process and a small V value.
    Journal of the American Chemical Society 08/2014; 136(38). DOI:10.1021/ja505391x · 11.44 Impact Factor
  • Shohei Tashiro · Tsutomu Umeki · Ryou Kubota · Mitsuhiko Shionoya
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    ABSTRACT: Porous crystals are excellent materials with potential spatial functions through molecular encapsulation within the pores. Co-encapsulation of multiple different molecules further expands their usability and designability. Herein we report the simultaneous arrangement of up to three different guest molecules, TTF (tetrathiafulvalene), ferrocene, and fluorene, on the pore surfaces of a porous crystalline metal–macrocycle framework (MMF). The position and orientation of adsorbed molecules arranged in the pore were determined by single-crystal X-ray diffraction analysis. The anchoring effect of hydrogen bonds between the hydroxy groups of the guest molecules and inter-guest cooperation and competition are significant factors in the adsorption behaviors of the guest molecules. This finding would serve as a design basis of multicomponent functionalized nanospaces for elaborate reactions that are realized in enzymes.
    Angewandte Chemie 08/2014; 126(32). DOI:10.1002/ange.201404179
  • Shohei Tashiro · Tsutomu Umeki · Ryou Kubota · Mitsuhiko Shionoya
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    ABSTRACT: Porous crystals are excellent materials with potential spatial functions through molecular encapsulation within the pores. Co-encapsulation of multiple different molecules further expands their usability and designability. Herein we report the simultaneous arrangement of up to three different guest molecules, TTF (tetrathiafulvalene), ferrocene, and fluorene, on the pore surfaces of a porous crystalline metal-macrocycle framework (MMF). The position and orientation of adsorbed molecules arranged in the pore were determined by single-crystal X-ray diffraction analysis. The anchoring effect of hydrogen bonds between the hydroxy groups of the guest molecules and inter-guest cooperation and competition are significant factors in the adsorption behaviors of the guest molecules. This finding would serve as a design basis of multicomponent functionalized nanospaces for elaborate reactions that are realized in enzymes.
    Angewandte Chemie International Edition in English 08/2014; 53(32). DOI:10.1002/anie.201404179 · 13.45 Impact Factor
  • Shohei Tashiro · Mitsuhiko Shionoya
    ChemInform 07/2014; 45(27). DOI:10.1002/chin.201427293
  • Ryosuke Miyake · Mitsuhiko Shionoya
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    ABSTRACT: To understand reversible structural switching in crystalline materials, we studied the mechanism of reversible crystal-to-crystal transformation of a tetranuclear Ni(II) macrocycle consisting of artificial β-dipeptides. On the basis of detailed structural analyses and thermodynamic measurements made in a comparison of pseudo-isostructural crystals (NO3 and BF4 salts), we herein discuss how ligand-exchange reactions take place in the crystal due to changes in water content and temperature. Observations of the structural transformation of NO3 salt indicated that a pseudo crystalline phase transformation takes place through concerted ligand-exchange reactions at the four Ni(II) centers of the macrocycle with hydrogen bond switching. A mechanism for this ligand exchange was supported by IR spectroscopy. Thermodynamic measurements suggested that the favorable compensation relationship of the enthalpy changes due to water uptake and structural changes are keys to the reversible structural transformation. On the basis of a comparison with the pseudo-isostructural crystals, it is apparent that the crystal packing structure and the types of counter anions are important factors for facilitating reversible ligand exchange with single crystallinity.
    Inorganic Chemistry 06/2014; 53(11):5717-23. DOI:10.1021/ic500478p · 4.79 Impact Factor
  • Elizabeth M Nolan · Mitsuhiko Shionoya
    Current opinion in chemical biology 04/2014; 19. DOI:10.1016/j.cbpa.2014.03.016 · 7.65 Impact Factor
  • Takashi Nakamura · Hitoshi Ube · Ryosuke Miyake · Mitsuhiko Shionoya
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    ABSTRACT: Coordination-driven self-assembly utilizing labile capping ligands has been exploited as a novel strategy for metallo-cage containers. Herein, we report a tetrameric porphyrin barrel complex [C60⊂Zn814(H2O)4(OTs)12](OTs)4 (2) (OTs = p-CH3C4H6SO3) formed from a tetrakis(bipyridyl)porphyrin ligand 1, Zn(OTs)2, and a template guest, C60 fullerene. The tetrameric-barrel 2 contains two kinds of bis(bpy) ZnII centers coordinated by TsO- anions which serve as labile capping ligands in the formation of the finite structure of 2.
    Journal of the American Chemical Society 12/2013; 135(50). DOI:10.1021/ja4110446 · 11.44 Impact Factor
  • Takashi Nakamura · Hitoshi Ube · Mitsuhiko Shionoya
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    ABSTRACT: Guests welcome: Complex formation between Ag(I) ions and a Zn-porphyrin ligand (L) possessing four 2,2'-bipyridyl groups produced a dimeric complex [Ag4 L2 ](4+) , wherein the interplane distance between the Zn-porphyrin groups was ideal for intercalation of aromatic molecules through π-π interactions. The cofacial dimer [Ag4 L2 ](4+) serves as an excellent receptor for π-electron-deficient guests.
    Angewandte Chemie International Edition 11/2013; 52(46). DOI:10.1002/anie.201306510 · 11.26 Impact Factor
  • Source
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    ABSTRACT: The syntheses and properties of corannulenes carrying electron-withdrawing groups (F, CF3, C6F5 ) are reported. Direct fluorination of corannulene (C20H10) was carried out with xenon difluoride, and the crystal structure of the product was confirmed by the X-ray analysis. Novel trifluoromethylated corannulenes, including the versatile 4,9-dibromo-1,2-bis(trifluoromethyl)corannulene, were obtained by various established ring-closing reactions. Besides the use of hexafluorobutyne for the construction of fluoranthenes by Diels-Alder reaction as precursor molecules to form 1,2-disubstituted corannulenes, bis(pentafluorophenyl)acetylene was employed as dienophile. The molecular structure and crystal packing of a trifluoromethylated corannulene was determined by single-crystal X-ray analysis and compared with those known brominated and trifluoromethylated corannulenes. The general electron-acceptor properties of corannulenes bearing substituents introduced in particular positions by liquid-phase synthesis are discussed together with published computational results.
    Chemistry - A European Journal 09/2013; DOI:10.1002/chem.201301910 · 5.70 Impact Factor
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  • Shohei Tashiro · Ryou Kubota · Minori Kawagoe · Mitsuhiko Shionoya
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    ABSTRACT: Synthetic amphiphiles have been found to self-assemble into a variety of structures such as micelles, vesicles, cylinders and lamellae in aqueous media over many length scales. We report herein cation-induced aggregation of hexaaza-cyclophanes in water. Pd(2+)- or proton-induced formation of submicro spherical aggregates was observed by several spectroscopic and microscopic methods.
    Dalton Transactions 08/2013; 42(45). DOI:10.1039/c3dt51827b · 4.20 Impact Factor
  • Takashi Nakamura · Hitoshi Ube · Mitsuhiko Shionoya
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    ABSTRACT: Desymmetrization self-assembly of symmetric building blocks is a powerful method to construct elaborate metallosupramolecular architectures. Herein several examples are given to discuss how to build up self-assembled complexes with low symmetry, focusing on 1) stabilization of local structural motifs by template molecules and/or interligand interactions, 2) rigidity regulation of ligand scaffolds, and 3) control of intermediate complexation conditions. Unsymmetrically assembled supramolecular host complexes exhibit unique functions reflecting their structural frameworks.
    ChemInform 07/2013; 44(30). DOI:10.1002/chin.201330224
  • Masumi Kuritani · Shohei Tashiro · Mitsuhiko Shionoya
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    ABSTRACT: Stacked rings: A diamond-shaped macrocycle with two inward phenanthroline ligands and outward long alkyl chains, and its Pd(II) complex form organic and organometallic fibrous aggregates, respectively, as revealed by NMR, UV/Vis, AFM, and TEM measurements. The most likely structures are face-to-face stacked macrocycles, generating nanotubes.
    Chemistry - An Asian Journal 07/2013; 8(7). DOI:10.1002/asia.201300209 · 3.94 Impact Factor
  • Masumi Kuritani · Shohei Tashiro · Mitsuhiko Shionoya
    Chemistry - An Asian Journal 07/2013; 8(7):1333-1333. DOI:10.1002/asia.201390020 · 3.94 Impact Factor
  • Shohei Tashiro · Mitsuhiko Shionoya
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    ABSTRACT: Inspired by vital roles of metal ions as structure-stabilizing and regulating factors in biological systems, a great number of synthetic metallopeptides have been developed. This review focuses on metal-mediated stabilization and stimuli-responsive regulation of their secondary and higher-order structures by taking advantage of the characteristics of metal ions such as Lewis acidity, ligand-exchange ability, and redox properties.
    Chemistry Letters 05/2013; 42(5):456-462. DOI:10.1246/cl.130334 · 1.30 Impact Factor

Publication Stats

4k Citations
1,100.15 Total Impact Points

Institutions

  • 1999–2015
    • The University of Tokyo
      • Department of Chemistry
      Tōkyō, Japan
    • Kumamoto University
      • Department of Applied Chemistry and Biochemistry
      Kumamoto, Kumamoto, Japan
  • 2014
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 2000–2010
    • Nankai University
      • Department of Chemistry
      T’ien-ching-shih, Tianjin Shi, China
  • 1987–2010
    • Hiroshima University
      • • School of Medicine
      • • Department of Dental and Medical Biochemistry
      Hirosima, Hiroshima, Japan
  • 2000–2001
    • The Graduate University for Advanced Studies
      Миура, Kanagawa, Japan
  • 1998
    • Institute for Molecular Science
      Okazaki, Aichi, Japan
  • 1991
    • Shionogi & Co., Ltd.
      Ōsaka, Ōsaka, Japan