Updated on 2023/09/12

写真a

 
OKI Kosuke
 
Organization
Graduate School of Engineering Molecular and Macromolecular Chemistry 2 Designated assistant professor
Title
Designated assistant professor
External link

Degree 1

  1. 博士(理学) ( 2020.3   愛媛大学 ) 

Research Areas 2

  1. Nanotechnology/Materials / Structural organic chemistry and physical organic chemistry

  2. Nanotechnology/Materials / Polymer chemistry

Research History 1

  1. Nagoya University   Graduate School of Engineering Molecular and Macromolecular Chemistry 2   Designated assistant professor

    2021.6

Education 3

  1. Ehime University

    2017.4 - 2020.3

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    Country: Japan

  2. Ehime University

    2015.4 - 2017.3

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    Country: Japan

  3. Ehime University

    2011.4 - 2015.3

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    Country: Japan

 

Papers 15

  1. Optically-pure triptycene-based metallomacrocycles and homochiral self-sorting assisted by ladder formation

    Oki Kosuke, Zheng Wei, Yashima Eiji, Ikai Tomoyuki

    CHEMICAL COMMUNICATIONS   Vol. 59 ( 58 ) page: 8989 - 8992   2023.7

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    Language:English   Publisher:Chemical Communications  

    Optically-pure triptycene-based metallomacrocycles are, for the first time, synthesized by the coordination-driven self-assembly of enantiopure triptycene-derived ladder-type bis(benzo[f]isoquinoline) ligands with a cis-platinum(ii) complex. A pair of enantiomeric homochiral metallomacrocycles is also produced by the coordination-driven homochiral self-sorting of the corresponding racemic ligands, which relies on the shape-persistent nature of the ladder-structured ligands.

    DOI: 10.1039/d3cc02259e

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  2. Substituent Effects on Paratropicity and Diatropicity in π-Extended Hexapyrrolohexaazacoronen Reviewed International journal

    Masayoshi Takase, Toranosuke Takata, Kosuke Oki, Shigeki Mori, Hidemitsu Uno

    Chemical Science   Vol. 14 ( 25 ) page: 7036 - 7043   2023.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    DOI: 10.1039/d2sc07037e

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  3. One-Handed Helical Polyacetylenes Bearing Axially-Chiral 2-Arylpyridyl-N-Oxide Units for Efficient Chromatographic Enantioseparation of Chiral Aromatic and Aliphatic Alcohols

    Ikai Tomoyuki, Ito Masaki, Oki Kosuke, Suzuki Nozomu, Yashima Eiji

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   Vol. 62 ( 31 ) page: e202306252   2023.6

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    Language:English   Publisher:Angewandte Chemie - International Edition  

    A series of poly(biarylylacetylene)s (PBAs) bearing axially-chiral (S)-and (R)-pyridyl-N-oxide residues with a methoxy, propoxy, or acetyloxy substituent at the 3-position of the biaryl units was synthesized. All the PBAs formed a preferred-handed helix, while the helical sense preference was varied depending on the substituents despite the same twist-sense of the biaryl units. Among them, the propoxy-bound helical PBA showed an exceptionally high chiral recognition ability as a chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) and efficiently resolved not only various chiral aromatic alcohols, but also a variety of chiral aliphatic alcohols; the latter still remains difficult to resolve by commercially-available CSPs in HPLC. Such practically-useful both handed helical PBA-based CSPs can be produced from the racemic PBA composed of fully racemic monomer units through deracemization of the biaryl units with a chiral alcohol.

    DOI: 10.1002/anie.202306252

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  4. Amplification of macromolecular helicity of poly(biphenylylacetylene)s composed of a small amount of chiral [5]helicene units

    Ikai Tomoyuki, Anzai Shun, Oki Kosuke, Yashima Eiji

    JOURNAL OF POLYMER SCIENCE   Vol. 61 ( 10 ) page: 912 - 919   2023.5

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    Publisher:Journal of Polymer Science  

    A series of novel biphenylylacetylene (BPA)-based chiral/achiral copolymers bearing a small amount of configurationally labile optically active [5]helicene pendants (5, 10, and 20 mol%) introduced at the 4′-position of the biphenyl units was synthesized. An almost fully right (P)-handed helical copolymer was obtained when copolymerized with 10 mol% of the (M)-[5]helicene-bound BPA monomer, indicative of a very strong sergeants and soldiers effect. The (M)-helicene units of the copolymers are configurationally labile and gradually racemized over time. However, the copolymer with 10 mol% of the (M)-[5]helicene-bound BPA mostly maintained its preferred-handed helicity even after the pendant helicene units were completely racemized, which can be ascribed to the static memory of the main-chain helicity stabilized by the bulky yet racemic helicene units. Hence, the helicity memory of the corresponding helicene-free homopolymer was lost rapidly. For comparison, an optically inactive copolymer containing 10 mol% of the racemic [5]helicene units was also prepared, and noncovalent helicity induction and subsequent memory of the helicity as well as its helix-memory stability were investigated.

    DOI: 10.1002/pol.20220658

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  5. Defect-Free Synthesis of a Fully p-Conjugated Helical Ladder Polymer and Resolution into a Pair of Enantiomeric Helical Ladders

    Ikai Tomoyuki, Miyoshi Sayaka, Oki Kosuke, Saha Ranajit, Hijikata Yuh, Yashima Eiji

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   Vol. 62 ( 20 ) page: e202301962   2023.5

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    Language:English   Publisher:Angewandte Chemie - International Edition  

    Fully π-conjugated ladder polymers with a spiral geometry represent a new class of helical polymers with great potential for organic nanodevices, but there is no precedent for an optically active helical ladder polymer totally composed of achiral units. We now report the defect-free synthesis and resolution of a fully π-conjugated helical ladder polymer with a rigid helical cavity, which has been achieved by quantitative and chemoselective acid-promoted alkyne benzannulations of a rationally designed, random-coil achiral polymer followed by chromatographic enantioseparation. Because of a sufficiently high helix-inversion barrier, the isolated excess one-handed helical ladder polymer with a degree of polymerization of more than 15 showed a strong circular dichroism with a dissymmetry factor of up to 1.7×10−2 and is thermally stable, maintaining its optical activity in solution even at 100 °C, as well-supported by molecular dynamics simulation.

    DOI: 10.1002/anie.202301962

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  6. Remote Control of One-Handed Helicity in Polyacetylenes through Flexible Spacers in Water: Impact of the Spacer Length

    Ikai Tomoyuki, Nakamura Koshi, Mizumoto Kosuke, Oki Kosuke, Yashima Eiji

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   Vol. 62 ( 20 ) page: e202301127   2023.5

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    Language:English   Publisher:Angewandte Chemie - International Edition  

    We report the unprecedented sergeants and soldiers (S&S)-type remote control of one-handed helicity in copolymers of chiral/achiral biphenylylacetylenes bearing amphiphilic oligo(ethylene glycol) (OEG) side chains. A small amount of chiral binaphthyl residues (≤10 mol %) introduced at the terminal of the achiral OEG spacers as many as 80 bonds away from the polymer backbones induced a complete one-handed helix in water through preferential intramolecular encapsulation of the binaphthyl groups within a cavity of the copolymers. A fully one-handed helix can be induced virtually independent of the OEG spacer length and concentrations. At a specific spacer length, however, its helix-sense was inverted. The copolymers also form an excess one-handed helix in organic solvents in an OEG spacer-length dependent manner, yet far from the polymer backbones. We show the superiority of the present covalent-bond driven S&S-type remote helicity control over the corresponding noncovalent helicity induction approach.

    DOI: 10.1002/anie.202301127

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  7. Stereospecific Synthesis of Enantiopure [6]Helicene Containing a Seven-Membered Ring and [7]Helicene by Acid-Promoted Stepwise Alkyne Annulations of Doubly Axial-Chiral Precursors

    Ikai Tomoyuki, Oki Kosuke, Yamakawa Shoya, Yashima Eiji

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   Vol. 62 ( 18 ) page: e202301836   2023.3

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    Language:English   Publisher:Angewandte Chemie - International Edition  

    Enantiopure [6]helicene containing an embedded seven-membered ring and carbo[7]helicene (>99 % ee) with opposite helicity were simultaneously and quantitatively (>99 %) synthesized with a perfect stereospecificity through stepwise acid-promoted intramolecular alkyne annulations of doubly axial-chiral cyclization precursors. The helical handedness of the [6]- and [7]helicenes was fully stereocontrolled by the doubly axial chirality of the precursors as a result of complete axial-to-helical chirality transfer. The cyclizations proceeded in a stepwise manner; the first six-membered ring formation was followed by the kinetically controlled seven- or six-membered ring formation with or without helix-inversion of a [4]helicene intermediate generated during the first cyclization step, thus quantitatively producing enantiopure circularly polarized luminescent [6]- and [7]helicenes with opposite helicity.

    DOI: 10.1002/anie.202301836

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  8. One-Handed Helical Tubular Ladder Polymers for Chromatographic Enantioseparation

    Zheng Wei, Oki Kosuke, Saha Ranajit, Hijikata Yuh, Yashima Eiji, Ikai Tomoyuki

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   Vol. 62 ( 11 ) page: e202218297   2023.3

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    Language:English   Publisher:Angewandte Chemie - International Edition  

    Defect-free one-handed contracted helical tubular ladder polymers with a π-electron-rich cylindrical helical cavity were synthesized by alkyne benzannulations of the random-coil precursor polymers containing 6,6′-linked-1,1′-spirobiindane-7,7′-diol-based chiral monomer units. The resulting tightly-twisted helical tubular ladder polymers showed remarkably high enantioseparation abilities toward a variety of chiral hydrophobic aromatics with point, axial, and planar chiralities. The random-coil precursor polymer and analogous rigid-rod extended helical ribbon-like ladder polymer with no internal helical cavity exhibited no resolution abilities. The molecular dynamics simulations suggested that the π-electron-rich cylindrical helical cavity formed in the tightly-twisted tubular helical ladder structures is of key importance for producing the highly-enantioseparation ability, by which chiral aromatics can be enantioselectively encapsulated by specific π-π and/or hydrophobic interactions.

    DOI: 10.1002/anie.202218297

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  9. Synthesis of a π-extended azacoronene composed of naphthalene and acenaphtho[1,2-<i>c</i>]pyrrole toward a chiral curved π structure

    Masayoshi Takase, Takayuki Matsunaga, Kosuke Oki, Shigeki Mori, Hidemitsu Uno

    Journal of Porphyrins and Phthalocyanines   Vol. 27 ( 1-4 ) page: 253 - 259   2022.12

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    Publishing type:Research paper (scientific journal)   Publisher:World Scientific Pub Co Pte Ltd  

    DOI: 10.1142/S1088424622500869

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  10. Tropo(thio)ne-Embedded HomoHPHACs: Does the Tropylium Cation Induce Global Antiaromaticity in Expanded Hexapyrrolohexaazacoronene?

    Masayoshi Takase, Atsushi Ueno, Kosuke Oki, Hiroki Matsumoto, Shigeki Mori, Tetsuo Okujima, Hidemitsu Uno

    Chemical Communications   Vol. 58 ( 20 ) page: 3366 - 3369   2022.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    Tropo(thio)ne-embedded homoHPHACs and their dications were synthesised by an electrophilic annulation of secoHPHAC and successive oxidation. 13C NMR spectra of the dications represented global 22π homoaromaticity via homoconjugation, while alkylation...

    DOI: 10.1039/d1cc07152a

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  11. Synthesis, Properties, and Packing Structures of Wing-Shaped N-Doped Nanographene in Various Oxidation States

    Fan Wu, Kosuke Oki, Jiaying Xue, Shigeki Mori, Masayoshi Takase, Zhen Shen, Hidemitsu Uno

    Organic Letters   Vol. 24 ( 1 ) page: 80 - 84   2022.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    A rigid wing-shaped bicyclo[2.2.2]octadiene-fused bis-hexapyrrolohexaazacoronene (HPHAC) is synthesized, and subsequent chemical oxidation affords a stable biradical dication and an aromatic tetracation. The physicochemical properties and single-crystal structures in various oxidation states are characterized. The face-to-face π-stacked dimeric structures are observed in the neutral and dicationic states. The HPHAC flakes can act as aromatic walls in a tetracation state, producing enlarged induced magnetic shielding space through the superimposition effect.

    DOI: 10.1021/acs.orglett.1c03669

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  12. Synthesis and Characterization of Peralkylated Pyrrole-Fused Azacoronene

    Kosuke Oki, Masayoshi Takase, Nagao Kobayashi, Hidemitsu Uno

    JOURNAL OF ORGANIC CHEMISTRY   Vol. 86 ( 7 ) page: 5102 - 5109   2021.4

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

    A hexapyrrolohexaazacoronene (HPHAC) with 12 less-bulky peripheral ethyl groups than its aryl-containing HPHAC counterpart was synthesized to investigate the innate character of HPHAC. X-ray diffraction analysis revealed that HPHAC had a planar structure and close packing because of CH-p interactions between the alkyl groups and the HPHAC core. Compared to the previously reported HPHAC decorated with 12 peripheral aryl groups, this electron-rich p-system exhibited reversible multistep oxidations at low potentials and easily formed mono- and dicationic salts and charge-transfer (CT) complexes with 7,7,8,8-tetracyano-p-quinodimethane. These oxidized species exhibited clear changes in the bond-length alternation of the pyrrole units in the crystal state, indicating charge and spin delocalization. The distinct upfield shift of the central carbon signal of the dication in the C-13 NMR spectrum affirms the global aromaticity from the viewpoint of a magnetic criterion. In the UV-vis/NIR spectra, broad absorption in the NIR region was observed only for HPHAC(2+) and not the structurally similar cyclo[6]pyrrole. Magnetic circular dichroism measurements and time-dependent density functional theory calculations revealed that the broad absorption was assigned to the CT transition from the central benzene ring to the outer pyrrole rings.

    DOI: 10.1021/acs.joc.0c03042

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  13. Synthesis and Isolation of Antiaromatic Expanded Azacoronene via Intramolecular Vilsmeier-Type Reaction

    Kosuke Oki, Masayoshi Takase, Shigeki Mori, Hidemitsu Uno

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   Vol. 141 ( 41 ) page: 16255 - 16259   2019.10

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

    An antiaromatic cation of the expanded hexapyrrolohexaazacoronene (HPHAC) 1(+) was synthesized by a Vilsmeier-type reaction of the partially unfused HPHAC 2. X-ray diffraction analysis revealed the formation of a seven-membered ring with a methyne linkage between the pyrrole moieties. Although 1(+) is a monocation, upfield shifts of the peripheral ethyl protons were clearly observed in the H-1 NMR spectra, indicating 24 pi antiaromaticity. Global antiaromaticity was also supported by nucleus-independent chemical shift and anisotropy of the induced current density calculations. Cation 1(+) displayed two reversible oxidations and one irreversible reduction in the cyclic voltammetry measurements. Treatment of 1(+) with NOSbF6 gave aromatic trication 1(3+) with 22 pi-electron conjugation.

    DOI: 10.1021/jacs.9b09260

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  14. Synthesis, Structures, and Properties of Core-Expanded Azacoronene Analogue: A Twisted pi-System with Two N-Doped Heptagons

    Kosuke Oki, Masayoshi Takase, Shigeki Mori, Akitoshi Shiotari, Yoshiaki Sugimoto, Keishi Ohara, Tetsuo Okujima, Hidemitsu Uno

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   Vol. 140 ( 33 ) page: 10430 - 10434   2018.8

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

    A core-expanded, pyrrole-fused azacoronene analogue containing two unusual N-doped heptagons was obtained from commercially available octafluoronaphthalene and 3,4-diethylpyrrole in two steps as a heteroatom-doped nonplanar nanographene. Full fusion with the formation of the tetraazadipleiadiene framework and the longitudinally twisted structure was unambiguously confirmed by single-crystal X-ray diffraction analysis. The edge-to-edge dihedral angle along the acene moiety was 63 degrees. This electron-rich pi-system showed four reversible oxidation peaks. Despite the nonplanar structure, the Huckel aromaticity owing to a peripheral pi-conjugation in the dicationic state was concluded from the bond-length alternation and nucleus-independent chemical shift (NICS) and anisotropy of the induced current density (ACID) calculations.

    DOI: 10.1021/jacs.8b06079

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  15. One-pot Synthesis of a Rice-ball-shaped Cyclophane with syn-Diethanoanthracene-fused Dipyrrole and Hexafluorobenzene

    Kosuke Oki, Kazunari Tagawa, Shigeki Mori, Masayoshi Takase, Tetsuo Okujima, Hidemitsu Uno

    CHEMISTRY LETTERS   Vol. 46 ( 2 ) page: 243 - 244   2017.2

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

    A cyclophane composed of diethanoanthracene (DEA)-fused dipyrrole and tetrafluorobenzene was synthesized by one-pot aromatic nucleophilic substitution (SNAr). Reflecting the fixed angle of DEA-fused dipyrrole, X-ray single-crystal structure analysis of the cyclophane revealed its rice-ball-shaped structure.

    DOI: 10.1246/cl.161026

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KAKENHI (Grants-in-Aid for Scientific Research) 1

  1. ピロールを基軸とした含窒素湾曲ナノカーボンの創製

    Grant number:19J14288  2019.4 - 2021.3

    科学研究費助成事業  特別研究員奨励費

    沖 光脩

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    Authorship:Other 

    本研究は、(1)湾曲した分子構造を有するピロール縮環π電子系化合物の構築、(2)ねじれキラリティーを持ったカルバゾールオリゴマーの合成を主な研究目的としている。(1)においては、すでにナフタレンを中心骨格とするπ拡張アザコロネンを報告しているため、同様にアントラセンやコラニュレンを中心骨格とするπ拡張アザコロネンの合成に取り組む。そして、湾曲構造による光学特性、芳香族性などへの影響を調査する。(2)においては、芳香族求核置換反応を用いて立体的に込み入ったカルバゾールオリゴマーを合成することで、短段階でキラリティーを有するプロペラ状π電子系を構築し、円偏光発光特性の発現を目指す。
    昨年度に引き続き、含窒素ナノカーボンであるヘキサピロロヘキサアザコロネン(HPHAC)及びそのπ拡張類縁体の創製に取り組んだ。具体的には(1)アルキル側鎖を有するHPHACの合成、(2)湾曲構造を持つπ拡張アザコロネン類の構築を研究目的とした。
    (1)においては、これまで立体の大きなアリール基を側鎖とするHPHACが主に研究されていたのに対して、エチル基を側鎖とするドデカエチルHPHAC及びそのラジカルカチオン、ジカチオン、TCNQとの電荷移動錯体を合成した。合成したHPHACのX構造解析の結果、立体障害の小さいエチル基であっても、密に存在することでHPHAC同士のπ-πスタックを妨げることが明らかになった。また、HPHACジカチオンの吸収スペクトルにおける近赤外領域の幅広い吸収が分子内CT遷移に由来することをTD-DFT計算及びMCD測定によって明らかにした。(2)においては、1,2,3,4,5,6,7,8-オクタフルオロアントラセンと3,4-ジエチルピロールとの芳香族求核置換反応と続く酸化的渡環反応によって、折れ曲がり構造を示す含窒素湾曲分子が得られた。CV測定では可逆な4段階の1電子酸化過程を示した。また、酸化剤を用いた化学的酸化によりテトラカチオンを単離することに成功し、NMR測定によって確認した。一方、9,10-ジクロロオクタフルオロアントラセンに同様の反応を行うと、アントラセンを中心骨格とするπ拡張アザコロネン類縁体が得られた。X線構造解析の結果、分子内に2カ所ヘプタレン骨格が形成され、大きくねじれた構造であることがわかった。また、この大きなねじれ構造のため、ジカチオン状態やテトラカチオン状態でジラジカル性が発現するという特異な性質がDFT計算によって示唆された。このように、ピロールの反応性と構造を基軸とした含窒素湾曲ナノカーボンの創出に成功した。
    令和2年度が最終年度であるため、記入しない。
    令和2年度が最終年度であるため、記入しない。