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NAKAI Hidetaka

    Department of Energy and Materials　Professor
Last Updated :2024/04/25

Researcher Information

URL

J-Global ID

Research Interests

  • Solid-state reaction   Organometallic complexes   Photo-functional compounds   

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electronic devices and equipment
  • Nanotechnology/Materials / Functional solid-state chemistry
  • Nanotechnology/Materials / Inorganic and coordination chemistry

Academic & Professional Experience

  • 2023/04 - Today  Kindai UniversityFaculty of Science and Engineering, Department of Energy and MaterialsProfessor
  • 2016/04 - 2023/03  Kindai UniversityFaculty of Science and Engineering, Department of Applied Chemistry/Energy and MaterialsAssociate Professor
  • 2010/10 - 2016/03  Kyushu University大学院工学研究院 応用化学部門准教授
  • 2004/04 - 2010/09  Kanazawa University IInstitute of Science and Engineering, Faculty of Chemistry助教
  • 2003/10 - 2004/03  Osaka University大学院Postdoctoral fellow
  • 2002/02 - 2003/09  University of California, San DiegoPostdoctoral fellow
  • 2000/04 - 2002/01  Okazaki National Research InstitutesPostdoctoral fellow

Education

  •        - 2000/03  Kindai University  工学研究科  応用化学専攻
  •        - 1995/03  Kindai University  Faculty of Science and Engineering  Department of Applied Chemistry

Association Memberships

  • 日本化学会 有機結晶部会   複合系の光機能研究会   錯体化学会   日本化学会   The Chemical Society of Japan   Division of the Organic Crystals   Photofunctional Chemistry of Complex Systems   

Published Papers

  • Seiji Ogo; Takeshi Yatabe; Keishi Miyazawa; Yunosuke Hashimoto; Chiaki Takahashi; Hidetaka Nakai; Yoshihito Shiota
    JACS Au American Chemical Society (ACS) 2691-3704 2024/03
  • Chiaki Takahashi; Takeshi Yatabe; Hidetaka Nakai; Seiji Ogo
    Chemistry – A European Journal Wiley 29 (69) 0947-6539 2023/10 
    Abstract Chemists have long sought to regulate the reactivity of H2, to yield hydride ions, hydrogen atoms, or electrons on demand. One source of inspiration for achieving this control is [NiFe]hydrogenase ([NiFe]H2ase), which reacts with H2 to form various hydrogen active species such as NiIII hydride species, NiII hydride species, and NiI low‐valent species. Chemists have attempted to synthesize these hydrogen active species not only as models for the active species of [NiFe]H2ase, but also as electron transfer catalysts. However, the synthesis of NiI complex directly from H2 has not been reported. This paper reports the first example of a single‐step synthesis of a NiI complex, via reaction of a NiII complex with H2, stable for over 3 months at room temperature and we further demonstrate a reductive coupling of acridinium ions as part of a reaction cycle.
  • Daiki Shimauchi; Takeshi Yatabe; Yuka Ikesue; Yuu Kajiwara; Taro Koide; Tatsuya Ando; Ki-Seok Yoon; Hidetaka Nakai; Seiji Ogo
    Chemical Communications Royal Society of Chemistry (RSC) 1359-7345 2023 
    An H2-derived energy carrier that stores electrons from H2 at room temperature and transfers them to CO2 at leisure at room temperature.
  • Seiji Ogo; Takeshi Yatabe; Hidetaka Nakai
    Coordination Chemistry Reviews Elsevier BV 470 214697 - 214697 0010-8545 2022/11 [Refereed]
     
    In this review, we discuss whether the ligand design used in catalysts mimicking O2-tolerant [NiFe]hydrogenase ([NiFe]H2ase) can be applied to ligand design in catalysts for C–C bond forming reactions. First, we begin with a discussion of ligand design in catalysts that allow reductive activation of O2 by H2, using an O2-tolerant [NiFe]H2ase model catalyst. Next, we discuss whether this ligand design method- ology can be applied to reductive C–C coupling and C–H arylation reactions. Finally, we summarize the ligand design in the catalysts for reductive C–C coupling and C–H arylation reactions.
  • Yuu Kajiwara; Hikaru Yoshimizu; Kodai Matsumoto; Hidetaka Nakai
    Chemistry Letters The Chemical Society of Japan 51 (4) 372 - 374 0366-7022 2022/04 [Refereed]
     
    Rod-like millimeter-size crystal (2.0 mm (length) x 13 μm (width) x 31 μm (depth)) of a newly prepared photochoromic rhodium dithionite complex with n-methoxybutyl moieties shows the bending and unbending upon photoirradiation from the same side of the crystal; the bending mechanism was clarified by single crystal X-ray diffraction experiments.
  • Yuu Kajiwara; Hidetaka Nakai
    CrystEngComm Royal Society of Chemistry (RSC) 24 (7) 1437 - 1441 2022/02 [Refereed]
     
    The crystalline-state photochromism of 1MPro in the β-crystal was successfully disclosed by time-dependent X-ray diffraction experiments.
  • Yuu Kajiwara; Hidetaka Nakai
    Bulletin of the Chemical Society of Japan The Chemical Society of Japan 95 (1) 169 - 174 0009-2673 2022/01 [Refereed]
  • Shogo Yagura; Naoki Hayakawa; Airi Kuroda; Kei Ota; Rhota Tanishita; Genya Urasaki; Tsukasa Nakahodo; Hidetaka Nakai; Manabu Hoshino; Daisuke Hashizume; Tsukasa Matsuo
    Dalton Transactions Royal Society of Chemistry (RSC) 51 (48) 18633 - 18641 1477-9226 2022 [Refereed]
     
    We present the synthesis, structural features and absorption properties of a series of (E)-1,2-diaryldigermenes supported by the fused-ring bulky Eind groups.
  • Yuu Kajiwara; Seiya Miyata; Hidetaka Nakai
    Dalton Transactions Royal Society of Chemistry (RSC) 51 (1) 48 - 52 1477-9226 2022 [Refereed]
     
    A reversible conformational change of an n-methoxypropyl moiety during the course of thermal back reactions was observed by time-dependent X-ray diffraction experiments.
  • Takeshi Yatabe; Tamon Tome; Yukina Takahashi; Takahiro Matsumoto; Ki‐Seok Yoon; Hidetaka Nakai; Seiji Ogo
    Chemistry – A European Journal Wiley 27 (69) 17326 - 17330 0947-6539 2021/12 [Refereed]
  • Takeshi Yatabe; Sayaka Futakuchi; Keishi Miyazawa; Daiki Shimauchi; Yukina Takahashi; Ki-Seok Yoon; Hidetaka Nakai; Seiji Ogo
    RSC Advances Royal Society of Chemistry (RSC) 11 (62) 39450 - 39454 2021/12 [Refereed]
     
    Four requirements for the reductive C(sp3)–C(sp3) homo-coupling of benzyl/allyl halides in aqueous solution by using H2 as an electron source are described.
  • Ryoma Ohno; Yasuyuki Numata; Shigeaki Konaka; Shogo Yagura; Airi Kuroda; Mao Harada; Naoko Fujita; Naoki Hayakawa; Hidetaka Nakai; Alfredo Rosas-Sánchez; Daisuke Hashizume; Tsukasa Matsuo
    Bulletin of the Chemical Society of Japan The Chemical Society of Japan 94 (7) 1931 - 1939 0009-2673 2021/07 [Refereed]
  • Hidetaka Nakai; Yuu Kajiwara; Seiya Miyata
    CRYSTENGCOMM ROYAL SOC CHEMISTRY 23 (21) 3790 - 3793 2021/06 [Refereed]
     
    Crystalline-state photoreaction of a newly prepared organorhodium dithionite complex with n-hexyltetramethyl-cyclopentadienyl (Cp-Hex: eta(5)-C(5)Me(4)n-Hexyl) ligands was studied by single crystal X-ray diffraction experiments; 2 pi/5 rotation of the Cp-Hex ligand is induced by the photoisomerization of the dithionite group (mu-O2SSO2).
  • Hidetaka Nakai; Seiya Miyata; Yuu Kajiwara; Yoshiki Ozawa; Masaaki Abe
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 49 (6) 1721 - 1725 1477-9226 2020/02 [Refereed]
     
    Crystalline-state photochromism of a rhodium dithionite complex with n-propyl moieties was studied directly by performing single crystal X-ray diffraction experiments; a non-linear relationship between the degree of the conformational change of the n-propyl moiety and the degree of the photochromic reaction of the dithionite group (mu-O2SSO2) was observed at -173 degrees C.
  • Naoki Hayakawa; Tomohiro Sugahara; Yasuyuki Numata; Hotaka Kawaai; Kenta Yamatani; Shogo Nishimura; Shun Goda; Yuko Suzuki; Tomoharu Tanikawa; Hidetaka Nakai; Daisuke Hashizume; Takahiro Sasamori; Norihiro Tokitoh; Tsukasa Matsuo
    Dalton Transactions Royal Society of Chemistry (RSC) 47 (3) 814 - 822 1477-9226 2018/01 [Refereed]
     

    We present the transformation of low-coordinate germanium(ii) compounds.

  • Hidetaka Nakai; Masafumi Kuyama; Juncheol Seo; Takahiro Goto; Takahiro Matsumoto; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 46 (28) 9126 - 9130 1477-9226 2017/07 [Refereed]
     
    Taking advantage of the outstanding oxygen-sensitive luminescence properties of the previously synthesised Tb(III) complex [{((ArO)-Ar-MeMe)(3)tacn}Ln(III)(THF)] (1(Tb), Ln = Tb), herein, we have prepared an oxygen sensor based on 1(Tb) embedded in polystyrene film (1(Tb)/PS) and found that 1(Tb)/PS shows the highest sensitivity (I-0/I-100 = 14.9) and the fastest response (response/recovery time = 1.9 s/2.9 s), among the lanthanide(III)-based oxygen sensors with f-f emission. Moreover, we have prepared the lanthanide(III)-based colorimetric luminescent oxygen sensor (1(TbSm)/PS) with green-yellow-red responses, by using 1(Tb) and a newly synthesised oxygen-insensitive Sm(III) complex (1(Sm), Ln = Sm; Phi = 0.010 and tau = 12.2 mu s).
  • Koji Yoshimoto; Takeshi Yatabe; Takahiro Matsumoto; Viet-Ha Tran; Andrew Robertson; Hidetaka Nakai; Koichiro Asazawa; Hirohisa Tanaka; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 45 (37) 14620 - 14627 1477-9226 2016/10 [Refereed]
     
    We report the first example of a wholly inorganic mimic of a part of the FeMoco active centre of nitrogenases. We detail the synthesis, characterisation and reactivity of two related, transient hydride-containing inorganic clusters, a dihydride complex and a vinyl monohydride complex, which bear the [Fe2MoOS3] portion of FeMoco. The dihydride complex is capable of reducing acetylene to ethylene via the vinyl monohydride complex. In the reaction cycle, a transient low-valent complex was generated by the reductive elimination of H-2 or ethylene from dihydride or vinyl monohydride complexes, respectively.
  • Hidetaka Nakai; Kazuhiro Kitagawa; Juncheol Seo; Takahiro Matsumoto; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 45 (29) 11620 - 11623 1477-9226 2016/08 [Refereed]
     
    This paper presents a gadolinium(III) complex that shows blue phosphorescence in the crystalline state at room temperature under air atmosphere; color of the crystals can be changed to pale-green from blue by doping of 1-naphthol.
  • Hidetaka Nakai; Juncheol Seo; Kazuhiro Kitagawa; Takahiro Goto; Kyoshiro Nonaka; Takahiro Matsumoto; Seiji Ogo
    INORGANIC CHEMISTRY AMER CHEMICAL SOC 55 (13) 6609 - 6615 0020-1669 2016/07 [Refereed]
     
    Coordination environment of the Tb3+ ion in oxygen-sensitive luminescent complexes can be successfully controlled through the size of alkyl substituents on ligands {((ArOH)-Ar-Rme)(4)cyclen} (R = tBu or Me; cyclen = 1,4,7,10-tetraazacyclododecane); a newly prepared eight-coordinate complex 1(tBu) shows higher oxygen sensitivity (K-SV = 17 600) and lower luminescence quantum yield (Phi = 0.67 under N-2) = than those of the previously reported seven-coordinate analogues 1(Me) and [{((ArO)-Ar-MeMe)(3)tacn}Tb-III(THF)] (K-SV = 12 600 and 8300, Phi = 0.91 and 0.91 under N-2, respectively; tacn = 1,4,7-triazacyclononane; THF = tetrahydrofuran). The oxygen-sensitive mechanism is discussed on the basis of the photophysical properties of the corresponding Gd(III) complexes.
  • Hidetaka Nakai; Juncheol Seo; Kazuhiro Kitagawa; Takahiro Goto; Takahiro Matsumoto; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 45 (23) 9492 - 9496 1477-9226 2016/06 [Refereed]
     
    This paper presents the first dysprosium(III) complex, [{((ArO)-Ar-MeMe)(3)tacn}Dy-III(THF)] (1(Dy)), that shows oxygen-sensitive luminescence. The synthesis, structure and oxygen-sensitive luminescence properties of 1(Dy) are reported (Phi = 0.050 and tau = 17.7 mu s under N-2, Phi = 0.011 and tau = 4.1 mu s under O-2 and K-SV = 305 M-1 in THF; K-SV = 0.0077%(-1) in polystyrene film). The oxygen sensitive mechanism of 1(Dy) is discussed based on the photophysical properties of the corresponding gadolinium(III) complex, [{((ArO)-Ar-MeMe)(3)tacn} Gd-III(THF)].
  • Hidetaka Nakai; Kengo Matsuba; Masataka Akimoto; Tomonori Nozaki; Takahiro Matsumoto; Kiyoshi Isobe; Masahiro Irie; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 52 (23) 4349 - 4352 1359-7345 2016/03 [Refereed]
     
    Rod-like millimetre-size crystals of a newly prepared rhodium dithionite complex with n-pentyl moieties bend upon photoirradiation and return to the initial shape upon heating; the roles of the flexible n-pentyl moieties as well as the photoreactive dithionite unit (mu-O2SSO2) are disclosed by single crystal X-ray diffraction.
  • Koji Yoshimoto; Takeshi Yatabe; Takahiro Matsumoto; Andrew Robertson; Hidetaka Nakai; Hiromasa Tanaka; Takashi Kamachi; Yoshihito Shiota; Kazunari Yoshizawa; Koichiro Asazawa; Hirohisa Tanaka; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 45 (2) 149 - 151 0366-7022 2016/02 [Refereed]
     
    We report the first example of a µ-η1:η1-N2 dinuclear RuII complex with a polyamine ligand and elucidate the structure by means of X-ray analysis. The N≡N stretching vibration has been observed at 1994 cm−1 by Raman spectroscopy, which is the lowest value of all the known N2-coordinated RuII complexes. This low value strongly suggests the N≡N bond is primed for activation.
  • Takahiro Matsumoto; Koji Yoshimoto; Chunbai Zheng; Yasuhito Shomura; Yoshiki Higuchi; Hidetaka Nakai; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 45 (2) 197 - 199 0366-7022 2016/02 [Refereed]
     
    We report the synthesis, characterization, and reactivity of a NiRu monohydride complex with a pyridine-bound hexamethylbenzene ligand. We investigate the mechanistic insights it provides on the H2-activation of [NiFe]hydrogenase.
  • Keisuke Takashita; Takahiro Matsumoto; Takeshi Yatabe; Hidetaka Nakai; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 45 (2) 137 - 139 0366-7022 2016/02 [Refereed]
     
    We report the first example of a non-precious metal molecular catalyst for a fuel cell cathode. A nickel dihydrido complex is capable of reducing dioxygen to water through a four-electron pathway, as evidenced by an isotope-labeling experiment and electrochemical measurements.
  • Takahiro Kishima; Takahiro Matsumoto; Hidetaka Nakai; Shinya Hayami; Takehiro Ohta; Seiji Ogo
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION WILEY-V C H VERLAG GMBH 55 (2) 724 - 727 1433-7851 2016/01 [Refereed]
     
    Dioxygen-tolerant [NiFe] hydrogenases catalyze not only the conversion of H-2 into 2H(+) and 2e(-) but also the reduction of O-2 to H2O. Chemists have sought to mimic such bifunctional catalysts with structurally simpler compounds to facilitate analysis and improvement. Herein, we report a new [NiFe]-based catalyst for O-2 reduction via an O-2 adduct. Structural investigations reveal the first example of a side-on iron(IV) peroxo complex.
  • Keisuke Takashita; Takahiro Matsumoto; Takeshi Yatabe; Hidetaka Nakai; Masatatsu Suzuki; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 45 (1) 72 - 74 0366-7022 2016/01 [Refereed]
  • Takahiro Matsumoto; Tatsuya Ando; Yuki Mori; Takeshi Yatabe; Hidetaka Nakai; Seiji Ogo
    Journal of Organometallic Chemistry Elsevier BV 796 73 - 76 0022-328X 2015/11 [Refereed]
  • Takeshi Yatabe; Mitsuhiro Kikkawa; Takahiro Matsumoto; Keishi Urabe; Andrew Robertson; Hidetaka Nakai; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 44 (9) 1263 - 1265 0366-7022 2015/09 [Refereed]
  • Viet-Ha Tran; Takeshi Yatabe; Takahiro Matsumoto; Hidetaka Nakai; Kazuharu Suzuki; Takao Enomoto; Takashi Hibino; Kenji Kaneko; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 51 (63) 12589 - 12592 1359-7345 2015/08 [Refereed]
     
    We report an acid-stable Si oxide-doped Ir oxide film (IrSi oxide film), made by metal organic chemical vapour deposition (MOCVD) of an Ir-V complex for electrochemical water-oxidation. This is a successful improvement of catalytic ability and stability depending upon the pH of Ir oxide by doping of Si oxide. The turnover frequency (TOF) of the electrochemical water-oxidation by the IrSi oxide film is the highest of any Si oxide-doped Ir oxide materials and higher even than that of Ir oxide in acidic media.
  • Hidetaka Nakai; Kyoshiro Nonaka; Takahiro Goto; Juncheol Seo; Takahiro Matsumoto; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 44 (24) 10923 - 10927 1477-9226 2015/06 [Refereed]
     
    This paper presents a 1,4,7,10-teraazacyclododecane-based tetrakis-phenol as a protonated ligand precursor and its oxygen-sensitive luminescent terbium(III) complex with an extendable phenol pendant arm (Phi = 0.91 under N-2, Phi = 0.031 under air), in which the potentially N4O4-octadentate ligand unprecedentedly coordinates to the Tb3+ ion in a N4O3-heptadentate fashion.
  • Viet-Ha Tran; Takeshi Yatabe; Takahiro Matsumoto; Hidetaka Nakai; Kazuharu Suzuki; Takao Enomoto; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 44 (6) 794 - 796 0366-7022 2015/06 [Refereed]
     
    We report the first example of a Ni0 precursor that provides a contamination-free (<1%) nickel film by metal–organic chemical vapor deposition (MOCVD) using N2 as the carrier gas. The structure and physical properties of the Ni0 precursor and subsequent film are described.
  • Hidetaka Nakai; Takahiro Goto; Kazuhiro Kitagawa; Kyoshiro Nonaka; Takahiro Matsumoto; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 50 (99) 15737 - 15739 1359-7345 2014/12 [Refereed]
     
    This communication presents a new terbium(III) complex that shows the highest luminescence quantumyield among the oxygen-sensitive lanthanide complexes (Phi = 0.91 under N-2, Phi = 0.054 under air).
  • Nga T. Nguyen; Yuki Mori; Takahiro Matsumoto; Takeshi Yatabe; Ryota Kabe; Hidetaka Nakai; Ki-Seok Yoon; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 50 (87) 13385 - 13387 1359-7345 2014/11 [Refereed]
     
    We report the decomposition of formic acid to hydrogen and carbon dioxide, catalysed by a NiRu complex originally developed as a [NiFe]hydrogenase model. This is the first example of H-2 evolution, catalysed by a [NiFe]hydrogenase model, which does not require additional energy.
  • Harutaka Nakamori; Takahiro Matsumoto; Takeshi Yatabe; Ki-Seok Yoon; Hidetaka Nakai; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 50 (86) 13059 - 13061 1359-7345 2014/11 [Refereed]
     
    Herein, we report the first crystal structure of a monomeric p-semiquinonato d-block complex and its reactivity toward dioxygen, closely associated with a biological system of an oxygen evolving centre of photosystem II.
  • Hidetaka Nakai; Kihun Jeong; Takahiro Matsumoto; Seiji Ogo
    ORGANOMETALLICS AMER CHEMICAL SOC 33 (17) 4349 - 4352 0276-7333 2014/09 [Refereed]
     
    A new class of efficient catalyst, the Rh(I) complex [(eta(5)-C5Me5)Rh-I(bpy)] (1; bpy = 2,2'-bipyridine), for the C-F bond hydrogenolysis of fluoroaromatics (C6F5CF3, C6F6, C6F5H, and C6F5CH3) is presented. The best turnover number of 380 for C6F6 is afforded by using 0.1 mol % of 1, 0.8 MPa of H-2, and 2 equiv of Et2NH in CH3CN at 25 degrees C. The successful isolation of the C-F bond cleavage product [(eta(5)-C5Me5)Rh-III(bpy)(C6F5)](F) as a plausible intermediate of the catalytic hydrogenolysis of C6F6 by 1 is also described.
  • Takahiro Matsumoto; Shigenobu Eguchi; Hidetaka Nakai; Takashi Hibino; Ki-Seok Yoon; Seiji Ogo
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION WILEY-V C H VERLAG GMBH 53 (34) 8895 - 8898 1433-7851 2014/08 [Refereed]
     
    Reported herein is an electrode for dihydrogen (H-2) oxidation, and it is based on [NiFe] Hydrogenase from Citrobacter sp. S-77 ([NiFe](S77)). It has a 637 times higher mass activity than Pt (calculated based on 1 mg of [NiFe](S77) or Pt) at 50 mV in a hydrogen half-cell. The [NiFe](S77) electrode is also stable in air and, unlike Pt, can be recovered 100% after poisoning by carbon monoxide. Following characterization of the [NiFe](S77) electrode, a fuel cell comprising a [NiFe](S77) anode and Pt cathode was constructed and shown to have a a higher power density than that achievable by Pt.
  • Takeshi Yatabe; Takahiro Kikunaga; Takahiro Matsumoto; Hidetaka Nakai; Ki-Seok Yoon; Seiji Ogo
    Chemistry Letters The Chemical Society of Japan 43 (8) 1380 - 1382 0366-7022 2014/08 [Refereed]
  • Takeshi Yatabe; Mitsuhiro Kikkawa; Takahiro Matsumoto; Hidetaka Nakai; Kenji Kaneko; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 43 (8) 3063 - 3071 1477-9226 2014/02 [Refereed]
     
    We propose a model for the water-oxidation and recovery systems of the oxygen-evolving complex (OEC) of the photosystem II (PSII) enzyme. The whole system is constructed from two catalytic cycles, conducted as a tandem reaction: (i) a water-oxidation loop uses cerium(IV) ammonium nitrate as an oxidant to activate a dimanganese complex for water-oxidation and thereby liberate a molecule of O-2 and (ii) a recovery loop begins with photoinhibition of the dimanganese complex but then uses O-2 to reactivate the manganese centre. The net result is a catalytic water-oxidation catalyst that can use self-generated O-2 for recovery.
  • Takahiro Kikunaga; Takahiro Matsumoto; Takehiro Ohta; Hidetaka Nakai; Yoshinori Naruta; Kwang-Hyun Ahn; Yoshihito Watanabe; Seiji Ogo
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 49 (75) 8356 - 8358 1359-7345 2013/09 [Refereed]
     
    The first example of monooxygenation by a high-valent Mn-IV complex with a peroxide is described. A key Mn-IV acylperoxo intermediate, which uses m-chloroperoxybenzoic acid as the oxygen donor, is directly observed by electro-spray ionization mass spectrometry and resonance Raman spectroscopy.
  • Hidetaka Nakai; Kazuhiro Kitagawa; Harutaka Nakamori; Taisuke Tokunaga; Takahiro Matsumoto; Koichi Nozaki; Seiji Ogo
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION WILEY-V C H VERLAG GMBH 52 (33) 8722 - 8725 1433-7851 2013/08 [Refereed]
  • Daisuke Inoki; Takahiro Matsumoto; Hidetaka Nakai; Seiji Ogo
    European Journal of Inorganic Chemistry Wiley 2013 (22-23) 3978 - 3986 1434-1948 2013/08 [Refereed]
  • Takahiro Matsumoto; Kyoungmok Kim; Hidetaka Nakai; Takashi Hibino; Seiji Ogo
    ChemCatChem Wiley 5 (6) 1368 - 1373 1867-3880 2013/06 [Refereed]
  • Seiji Ogo; Koji Ichikawa; Takahiro Kishima; Takahiro Matsumoto; Hidetaka Nakai; Katsuhiro Kusaka; Takashi Ohhara
    SCIENCE AMER ASSOC ADVANCEMENT SCIENCE 339 (6120) 682 - 684 0036-8075 2013/02 [Refereed]
     
    Chemists have long sought to mimic enzymatic hydrogen activation with structurally simpler compounds. Here, we report a functional [NiFe]-based model of [NiFe] hydrogenase enzymes. This complex heterolytically activates hydrogen to form a hydride complex that is capable of reducing substrates by either hydride ion or electron transfer. Structural investigations were performed by a range of techniques, including x-ray diffraction and neutron scattering, resulting in crystal structures and the finding that the hydrido ligand is predominantly associated with the Fe center. The ligand's hydridic character is manifested in its reactivity with strong acid to liberate H-2.
  • Kyoungmok Kim; Takahiro Kishima; Takahiro Matsumoto; Hidetaka Nakai; Seiji Ogo
    ORGANOMETALLICS AMER CHEMICAL SOC 32 (1) 79 - 87 0276-7333 2013/01 [Refereed]
     
    We present two closely related series of a [NiFe] hydrogenase analogue. Based on a [NiRu] core, these complexes demonstrate inactivity, H-2 activation, or O-2 activation depending only on the nature of the Ru-coordinated aromatic ligand. It is demonstrated that even small changes made to this aromatic ligand can modulate the catalytic activity of the complex. Structural, electrochemical, kinetic, and thermodynamic studies reveal that differences in activation and binding modes of the substrates, combined with differences in a donation and lability of the aromatic ligands, result in abrupt changes in catalytic activity.
  • Satoshi Muratsugu; Zhihuan Weng; Hidetaka Nakai; Kiyoshi Isobe; Yuko Kushida; Takehiko Sasaki; Mizuki Tada
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS ROYAL SOC CHEMISTRY 14 (46) 16023 - 16031 1463-9076 2012/11 [Refereed]
     
    A novel oxide-supported Ir dimer, which was found to be active for transfer hydrogenation of aromatic ketones, was prepared on a gamma-Al2O3 surface from an Ir dimer complex [Ir-2{eta(5)-C-5(CH3)(5)}(2)(mu-CH2)(2)] (Ir-2) with an Ir=Ir bond. Detailed characterization of the gamma-Al2O3-supported Ir dimer (Ir-2/gamma-Al2O3) revealed that the structure of Ir-2 consisted of an Ir dimer with an Ir-Ir bond attached to the gamma-Al2O3 surface by two bridged Ir-(OAl)(2)-Ir bonds. The supported Ir-2/gamma-Al2O3 dimer with bridged Ir-(OAl)(2)-Ir bonds acted as an efficient catalyst for transfer hydrogenation (turnover number of acetophenone = 699 (24 h)), while homogeneous Ir-2, SiO2- and MgO-supported Ir-2 were much less active. A structural transformation at the interface of the Ir dimer and the gamma-Al2O3 surface was suggested to assist the transfer hydrogenation catalysis via the formation of an Ir-2-H-2 species on the gamma-Al2O3 surface (Ir-2-H-2/gamma-Al2O3) as a key intermediate in the transfer hydrogenation. The present study deepened the understanding of the role and dynamic behaviour of the oxide surface in the hydrogen transfer catalysis on the supported Ir dimer.
  • Kihun Jeong; Harutaka Nakamori; Shunsuke Imai; Takahiro Matsumoto; Seiji Ogo; Hidetaka Nakai
    Chemistry Letters The Chemical Society of Japan 41 (6) 650 - 651 0366-7022 2012/06 [Refereed]
  • Oanh P. Lam; Sebastian M. Franke; Hidetaka Nakai; Frank W. Heinemann; Wolfgang Hieringer; Karsten Meyer
    INORGANIC CHEMISTRY AMER CHEMICAL SOC 51 (11) 6190 - 6199 0020-1669 2012/06 [Refereed]
     
    An inverse trans influence has been observed in a high-valent U(V) imide complex, [(((ArO)-Ar-Ad)(3)N)U(NMes)]. A thorough theoretical evaluation has been employed in order to corroborate the ITI in this unusual complex. Computations on the target complex, [(((ArO)-Ar-Ad)(3)N)U(NMes)], and the model complexes [(((ArO)-Ar-Me)(3)N)U(NMes)] and [(NMe3)(OMe2)(OMe)(3)U(NPh)] are discussed along with synthetic details and supporting spectroscopic data. Additionally, the syntheses and full characterization data of the related U(V) trimethylsilylimide complex [(((ArO)-Ar-Ad)(3)N)U(NTMS)] and U(IV) azide complex [(((ArO)-Ar-Ad)(3)N)U(N-3)] are also presented for comparison.
  • Kyoungmok Kim; Takahiro Matsumoto; Andrew Robertson; Hidetaka Nakai; Seiji Ogo
    CHEMISTRY-AN ASIAN JOURNAL WILEY-V C H VERLAG GMBH 7 (6) 1394 - 1400 1861-4728 2012/06 [Refereed]
     
    Herein, we report a [NiRu] biomimetic system for O2-tolerant [NiFe]hydrogenases and demonstrate that electron donation to the [NiRu] center can switch the system between the activation of H2 and O2 through simple ligand effects by using hexamethylbenzene and pentamethylcyclopentadienyl ligands, respectively. Furthermore, we present the synthesis and direct observations of a [NiRu]peroxo species, which was formed by the oxygenation of a Ni-SIa model [NiRu] complex, that we propose as a biomimetic analogue of O2-bound species (OBS) of O2-tolerant [NiFe]hydrogenases. The [NiRu]peroxo complex was fully characterized by X-ray analysis, X-ray photoelectron spectroscopy (XPS), mass spectrometry, and 1H NMR spectroscopy. The OBS analogue was capable of oxidizing p-hydroquinone and sodium borohydride to turn back into the Ni-SIa model complex.
  • Daisuke Inoki; Takahiro Matsumoto; Hidetaka Nakai; Seiji Ogo
    ORGANOMETALLICS AMER CHEMICAL SOC 31 (8) 2996 - 3001 0276-7333 2012/04 [Refereed]
     
    A Rh-III monohydride terpyridine complex undergoes reductive elimination of H-2 in CH3CN to form a dinuclear Rh-II complex with a metal-metal bond. Kinetic studies have revealed that the conversion from the monohydride species to the dinuclear species with evolution of H-2 obeys first-order kinetics and have determined the kinetic deuterium isotope effect value to be 2.0. We discuss the mechanism for the reductive elimination of H-2 from rhodium hydride species.
  • Daisuke Inoki; Takahiro Matsumoto; Hideki Hayashi; Keisuke Takashita; Hidetaka Nakai; Seiji Ogo
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 41 (15) 4328 - 4334 1477-9226 2012/04 [Refereed]
     
    Reductive activation of O-2 by H-2 with rhodium terpyridine complexes in H2O and CH3CN is described and the mechanism is fully elucidated. The rhodium complex extracts electrons from H-2 and reductively activates O-2 to form a peroxo active intermediate. This intermediate is able to oxidise triphenyl phosphine to triphenyl phosphine oxide. A model system constructed in CH3CN provides isolable analogues of catalytic intermediates in H2O, allowing a detailed look at each step in the catalytic cycle.
  • Daisuke Inoki; Takahiro Matsumoto; Hidetaka Nakai; Seiji Ogo
    CHEMISTRY LETTERS CHEMICAL SOC JAPAN 41 (1) 116 - 118 0366-7022 2012/01 [Refereed]
     
    We report the synthesis of a mer-triaqua Rh-III complex using terpyridine as a meridional tridentate ligand. This is the first example of a structurally characterized six-coordinated mer-triaqua complex for any second- or third-row element from the main transition-metal groups (groups 5-11). This is also the first example of a structurally characterized mer-triaqua complex with terpyridine for any transition metal. Acid dissociation constants, pK(a1) and pK(a2), of the triaqua complex are determined to be 3.0 and 6.9, respectively.
  • Takeshi Yatabe; Masaki Karasawa; Kiyoshi Isobe; Seiji Ogo; Hidetaka Nakai
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 41 (2) 354 - 356 1477-9226 2012/01 [Refereed]
     
    A naphthyl-substituted pentamethylcyclopentadienyl ligand (Cp-Naph = eta(5)-C5Me4CH2C10H7) and its Sm(II) complexes [Sm(Cp-Naph)(2)(THF)(x)] (1: x = 2, 2: x = 0) have been prepared and characterised. The solvent-induced reversible conversion between the di-THF solvated purple complex 1 and the un-solvated dark green complex 2 is presented.
  • Takahiro Matsumoto; Ryota Kabe; Kyoshiro Nonaka; Tatsuya Ando; Ki-Seok Yoon; Hidetaka Nakai; Seiji Ogo
    INORGANIC CHEMISTRY AMER CHEMICAL SOC 50 (18) 8902 - 8906 0020-1669 2011/09 [Refereed]
     
    We propose a modified mechanism for the inhibition of [NiFe]hydrogenase ([NiFe]H(2)ase) by CO. We present a model study, using a NiRu H(2)ase mimic, that demonstrates that (i) CO completely inhibits the catalytic cycle of the model compound, (ii) CO prefers to coordinate to the Ru(II) center rather than taking an axial position on the Ni(II) center, and (iii) CO is unable to displace a hydrido ligand from the NiRu center. We combine these studies with a reevaluation of previous studies to propose that, under normal circumstances, CO inhibits [NiFe]H(2)ase by complexing to the Fe(II) center.
  • Hidetaka Nakai; Shinobu Uemura; Yousuke Miyano; Motohiro Mizuno; Masahiro Irie; Kiyoshi Isobe
    DALTON TRANSACTIONS ROYAL SOC CHEMISTRY 40 (10) 2177 - 2179 1477-9226 2011/03 [Refereed]
     
    A photoreactive rhodium dithionite complex [(RhCp(Et))(2)(mu-CH(2)) (2)(mu-O(2)SSO(2))] (1(Et)) with Cp(Et) (eta(5)-C(5)Me(4)Et) ligands was newly synthesized. Upon short-time irradiation with low intensity light, two kinds of stepwise surface morphology changes of the crystal 1(Et) were observed. Prolonged irradiation with high intensity light caused cracking and breaking down of the crystal.
  • Hidetaka Nakai; Saori Nakano; Shunsuke Imai; Kiyoshi Isobe
    ORGANOMETALLICS AMER CHEMICAL SOC 29 (19) 4210 - 4212 0276-7333 2010/10 [Refereed]
     
    Reduction of [Cp*(2)Ir(2)(mu-CH(2))(2)Cl(2)] (Cp* = eta(5)-C(5)Me(5)) with Na in benzene leads to the formation of a methylene-bridged iridium(I) dinuclear complex with a considerably short Ir-Ir double bond (2.4375(2) angstrom), [Cp*(2)Ir(2)(mu-CH(2))(2)], which reacts with alcohols (RCH(2)OH, R = H, Me, Et, Ph) to afford a unique cis-dihydride complex and the respective aldehyde (RCHO).
  • Takeshi Yatabe; Hidetaka Nakai; Koichi Nozaki; Tomoo Yamamura; Kiyoshi Isobe
    ORGANOMETALLICS AMER CHEMICAL SOC 29 (11) 2390 - 2393 0276-7333 2010/06 [Refereed]
     
    Lanthanide(III)bent-metallocene complexes with a novel photofunctionalized pentamethylcyclopentadienyl ligand having an N-phenylcarbazolyl group (Cp-PhCar = eta(5)-C5Me4CH2-C18H12N), [Ln(Cp-PhCar)(2)I(THF)] (Ln = Tb (1), Gd (2)), were prepared and their molecular structures and luminescence properties were investigated. The f-f emission from the terbium metal center of I was efficiently sensitized by Cp-PhCar (epsilon = 0.88 x 10(4) M-1 cm(-1) at 331 nm, Phi = 0.67 at 330 nm excitation, k(r) = 1.68 x 10(3) s(-1)). Additionally, the solid-state structure of potassium salts of C-5-ring (eta(5)-C5R5, R = Me, H) derivatives was uncommonly characterized in Cp-PhCar.
  • Hidetaka Nakai; Mayu Hatake; Yousuke Miyano; Kiyoshi Isobe
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY (19) 2685 - 2687 1359-7345 2009 [Refereed]
     
    An achiral photochromic dithionite (mu-O(2)SSO(2)) complex with n-propyl moieties forms chiral crystals and undergoes an enantioselective photoisomerization (ee > 90%) to an oxysulfur (mu-O(2)SOS*O) complex, containing an asymmetric S atom, with essentially 100% interconversion of the chiral crystals.
  • Hidetaka Nakai; Takashi Nonaka; Yousuke Miyano; Motohiro Mizuno; Yoshiki Ozawa; Koshiro Toriumi; Nobuaki Koga; Takanori Nishioka; Masahiro Irie; Kiyoshi Isobe
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY AMER CHEMICAL SOC 130 (52) 17836 - 17845 0002-7863 2008/12 [Refereed]
     
    In the crystalline state, the rhodium dinuclear complex [(RhCp*)(2)(mu-CH(2))(2)(mu-O(2)SSO(2))] (1) with a photoresponsive dithionite group (mu-O(2)SSO(2)) and two pentamethylcyclopentadienyl ligands (Cp* = eta(5)-C(5)Me(5)) undergoes a 100% reversible unimolecular type T inverse photochromism upon interconversion to [(RhCp*)(2)(mu-CH(2))(mu-O(2)SOSO)] (2). The photochromism can be followed directly by using stepwise crystal structure analysis (Angew. Chem., Int Ed. 2006, 45, 6473). In this study, we found that the photoreaction of 1 was triggered by absorption of the 510 nm light (charge transfer band from sigma(S-S) to sigma*(S-S) and e(Rh-Rh) orbitals assigned by DFT calculation) and included two important processes: kinetically controlled oxygen-atom transfer to produce four stereoisomers of 2 and thermodynamically controlled isomerization between the four stereoisomers of 2 to afford the most stable isomer. Although the formation rate of the four stereoisomer products was kinetically controlled and the population of the four stereoisomers produced in the system was thermodynamically controlled, both processes were regulated by the steric hindrance between the mu-O(2)SSO(2) or mu-O(2)SOSO ligand and the reaction cavity formed by the Cp* ligands. The cooperation of both processes achieved an intriguing stereospecific oxygen-atom rearrangement to produce only one stereoisomer of 2 at the final stage of the photoreaction at room temperature. We also determined the effect of the oxygen-atom rearrangement on the rotational motion of the two crystallographically independent Cp* ligands (parallel and perpendicular arrangement). Using variable-temperature (13)C CP/MAS NMR and quadrupolar echo solid-state (2)H NMR spectroscopies, before photoirradiation, the activation energies for the rotation of the parallel and perpendicular Cp* ligands in 1 were determined to be 33 +/- 3 and 7.8 +/- 1 kJ/mol, respectively, and after photoirradiation, in 2, they were much lower than those in 1 (21 +/- 2 and 4.7 +/- 0.5 kJ/mol, respectively). The large decrease in the activation energy for the parallel Cp* in 2 is attributed to the relaxation of molecular stress via a stereospecific oxygen-atom rearrangement, which suggests that the rotational motion of the Cp* ligands is coupled to the photochromism.
  • Yousuke Miyano; Hidetaka Nakai; Motohiro Mizuno; Kiyoshi Isobe
    CHEMISTRY LETTERS CHEMICAL SOC JAPAN 37 (8) 826 - 827 0366-7022 2008/08 [Refereed]
     
    Crystalline-state photoisomerization of a rhodium dithionite complex with benzyltetramethylcyclopentadienyl ligand, [((CpRh)-Rh-Bn)(2)(mu-CH2)(2)(mu-O2SSO2)] (Cp-Bn = eta(5)-C5Me4Bn), is studied by X-ray crystallography and CP/MAS C-13 NMR spectroscopy. The disorder of the Cp-Bn ring in the crystal and the crystal packing of the molecules of isomers produced by photoreaction play an important role for stabilization of the whole crystal.
  • Yousuke Miyano; Hidetaka Nakai; Yoshihito Hayashi; Kiyoshi Isobe
    JOURNAL OF ORGANOMETALLIC CHEMISTRY ELSEVIER SCIENCE SA 692 (1-3) 122 - 128 0022-328X 2007/01 [Refereed]
     
    A photoresponsive rhodium dinuclear complex having phenyltetramethylcyclopentadienyl (Cp-Ph = eta(5)-C5Me4Ph) and photosensitive dithionite (mu-O2SSO2) ligands, [((CpRh)-Rh-Ph)(2)(mu-CH2)(2)(mu-O2SSO2)] (1), has been synthesized. The crystal of complex 1 (monoclinic, C2/m (No. 12), a = 24.805(2) angstrom, b = 29.111(2) angstrom, c = 10.8475(11) angstrom, beta = 105.9830(7)degrees, V = 7530.0(12) angstrom(3), Z = 8) consists of two independent molecules, 1-cis and 1-trans, with different arrangement of the CpPh ligands. The flexibility, volume, and shape of the reaction cavities around the dithionite unit of 1-cis and 1-trans in the crystal are discussed. The crystal structures of the precursors of 1, trans[((CpRh)-Rh-Ph)(2)(mu-Cl)(2)Cl-2] and trans-[((CpRh)-Rh-Ph)(2)(mu-CH2)(2)Me-2], are also reported. (c) 2006 Elsevier B.V. All rights reserved.
  • Hidetaka Nakai; Motohiro Mizuno; Takanori Nishioka; Nobuaki Koga; Kimie Shiomi; Yousuke Miyano; Masahiro Irie; Brian K. Breedlove; Isamu Kinoshita; Yoshihito Hayashi; Yoshiki Ozawa; Takae Yonezawa; Koshiro Toriumi; Kiyoshi Isobe
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION WILEY-V C H VERLAG GMBH 45 (39) 6473 - 6476 1433-7851 2006/10 [Refereed]
  • Castro-Rodriguez, I; H Nakai; K Meyer
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION WILEY-V C H VERLAG GMBH 45 (15) 2389 - 2392 1433-7851 2006/04 [Refereed]
  • S Ogo; Y Takebe; K Uehara; T Yamazaki; H Nakai; Y Watanabe; S Fukuzumi
    ORGANOMETALLICS AMER CHEMICAL SOC 25 (2) 331 - 338 0276-7333 2006/01 [Refereed]
     
    The series of water-soluble palladacyclic aqua complexes [('Bu-SCS)Pd-II(H2O)](+) ([1](+), 'Bu-SCS = C6H3-2,6-(CH2S'Bu)(2)), [(Pr-i-SCS)Pd-II(H2O)](+) ([2](+), Pr-i-SCS = C6H3-2,6-((CH2SPr)-Pr-i)(2)), [(PCP)Pd-II(H2O)](+) ([3](+), PCP = C6H3-2,6-((OPPr2)-Pr-i)(2)), and [(PC)Pd-II(H2O)(2)](+) ([4](+), PC = 4-MeC6H3-2-((OPPr2)-Pr-i)) have been synthesized from the reaction of the corresponding palladacyclic chloro complexes with silver salts in water to optimize the catalytic activity for pH-dependent C-C coupling reactions in water by changing the supporting ligands from S-supporting (SCS) to P-supporting (PCP) ligands and also from tridentate (PCP) to bidentate (PC) ligands. It was confirmed that there was no precipitation of palladium black L under the present reaction conditions. The PC palladacyclic aqua complex [4](+) exhibits the highest catalytic activity among the water-soluble palladacyclic aqua complexes [1](+)-[4](+) for the pH-dependent Suzuki-Miyaura, Mizoroki-Heck, and Stille coupling reactions in water. This is one of the highest catalytic activities ever reported for coupling reactions with water-soluble palladium catalysts in water. The catalytic ability of the palladacyclic aqua catalysts is drastically dependent on the pH of the solution and the structures of supporting ligands. The structures of palladacyclic aqua and chloro complexes were unequivocally determined by X-ray analysis.
  • SATAKE Yuh; NAKAI Hidetaka; ITO Seishiro; FUJIHARA Hisashi
    Journal of the Japan Society of Colour Material 一般社団法人 色材協会 78 (11) 507 - 513 0010-180X 2005/11 [Refereed]
     
    Redox-active gold nanoparticles containing tetrathiafulvalene as an electron donor (TTF-Au nanoparticles) and fullerene C<SUB>60</SUB> as an electron acceptor (C<SUB>60</SUB>-Au nanoparticles) have been prepared by the reaction of octanethiol-stabilized gold nanoparticles with a tetrathiafulvalenyl-monothiol and a fullerene C<SUB>60</SUB>-terminated alkanethiol. Immersion of a gold electrode in a solution of the colloidal TTF-Au nanoparticles deposited the colloid films of them on the electrode surface, which were remarkably stable under repeated electrochemical cycling. Analogously, the self-assembly of C<SUB>60</SUB>-Au on planar gold surface led to the formation of the nanoparticle films which showed two distinct reversible reduction/oxidation waves and significant electrochemical stability. The electrochemical responses for the C<SUB>60</SUB>-Au nanoparticle films and self-assembled monolayers of the C<SUB>60</SUB>-thiol adsorbed on gold electrodes are significantly different. The nanocomposite films containing electron-donor and -acceptor functions such as TTF-Au and C<SUB>60</SUB>-Au can be characterized by cyclic voltammetry.
  • B Kure; S Ogo; D Inoki; H Nakai; K Isobe; S Fukuzumi
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY AMER CHEMICAL SOC 127 (41) 14366 - 14374 0002-7863 2005/10 [Refereed]
     
    An open capsule-type octanuclear heterometallic sulfide cluster without an intramolecular inversion center [Ru(eta(6)-C6Me6){P(OMe)(3)},{MoO(mu(3)-S)(3)}(Cul)(2)}(2) (5) has been synthesized for the first time by stepwise connection of three mononuclear building blocks, i.e., (i) [RuCl2(eta(6)-C6Me6){P(OMe)(3)}] (1a) as an octahedral terminal building block to control the direction of cluster expansion, (ii) [MoOS3](2-) as a tetrahedral polydentate building block owing to the strong coordination ability of the S atoms, and (iii) a Cul building block to form a trigonal planar (mu-S)(2)Cul unit or to form a linkage unit of two incomplete cubane-type octanuclear frameworks. The stepwise connection was made in the following order: [RuCl2(eta(6)-C6Me6){P(OMe)(3)}] (1a, mononuclear) -> [Ru(eta(6)-C6Me6){P(OMe)(3)},{MoOS(mu(2)-S)(2)}] (2a, dinuclear) -> [Ru(eta(6)-C6Me6){P(OMe)(3)},{MoO(mu(2)-S)(2)(mu(3)-S)}Cul] (3a, butterfly-type trinuclear) -> [Ru(eta(6)-C6Me6){P(OMe)(3)},{MoO(mu(3)-S)(3)}(Cul)(2)](2) (5). When P(OMe)(3) was replaced by P(OEt)(3), which is more bulky than P(OMe)(3), in the starting ruthenium building block [RuCl2(eta(6)-C6Me6){P(OEt)(3))] (1b, mononuclear), only the tetranuclear incomplete single cubane cluster [Ru(eta(6)-C6Me6){P(OEt)(3)},{MoO(mu(3)-S)(3)}(Cul)(2)] (6) was generated, owing to the steric effect of P(OEt)(3).
  • SA Cortes; MAM Hernandez; H Nakai; Castro-Rodriguez, I; K Meyer; AR Fout; DL Miller; JC Huffman; DJ Mindiola
    INORGANIC CHEMISTRY COMMUNICATIONS ELSEVIER SCIENCE BV 8 (10) 903 - 907 1387-7003 2005/10 [Refereed]
     
    A family of neutral and cationic Ti(IV) complexes supported by the sterically demanding and trianionic ligand (O3N)(3-)(O3N3-(O3N3- = tris(2-0,3-Ad,5-tBubenzyl)amine, Ad = 1-adamantyl) have been prepared from the hydrolysis of TiCl4(THF)(2) with the free base (O3N)H-3 and excess NEt3, followed by anion exchange reactions. These (O3N)Ti+ cores are resistant to moisture and air, are mononuclear, and possess C-3 symmetry on the NMR timescale. (c) 2005 Elsevier B.V. All rights reserved.
  • Castro-Rodriguez, I; H Nakai; LN Zakharov; AL Rheingold; K Meyer
    SCIENCE AMER ASSOC ADVANCEMENT SCIENCE 305 (5691) 1757 - 1759 0036-8075 2004/09 [Refereed]
     
    The electron-rich, six-coordinate tris-aryloxide uranium(III) complex [(((ArO)-Ar-Ad)(3)tacn)U-III] [where ((ArOH)-Ar-Ad)(3)tacn = 1,4,7-tris(3-adamantyl-5-tert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane] reacts rapidly with CO, to yield [(((ArO)-Ar-Ad)(3)tacn)U-IV(CO2)], a complex in which the CO2 ligand is linearly coordinated to the metal through its oxygen atom (eta(1)-OCO). The latter complex has been crystallographically and spectroscopically characterized. The inequivalent O-C-O bond lengths [1.122 angstroms (Angstrom) for the O-C bond adjacent to uranium and 1.277 Angstrom for the other], considered together with magnetization data and electronic and vibrational-spectra, support the following bonding model: U-IV=O=C-.-O- H <----> U-IV-O=C-O-. In these charge-separated resonance structures, the uranium center is oxidized to uranium(IV) and the CO2 ligand reduced by one electron.
  • H Nakai; XL Hu; LN Zakharov; AL Rheingold; K Meyer
    INORGANIC CHEMISTRY AMER CHEMICAL SOC 43 (3) 855 - 857 0020-1669 2004/02 [Refereed]
     
    Reaction of [(((Ad)ArO)(3)tacn)U(III)] (1) or [((Me(3)Si)(2)N)(3)U(III)] (3) with tetramethylimidazol-2-ylidene (Me(4)IMC:) yields novel N-heterocyclic carbene complexes [((Ad ArO)(3)tacn)U(III)(Me(4)IMC:)] (2) and [((Me(3)Si)(2)N)(3)U(III)(Me(4)IMC:)] (4). Uranium complexes 2 and 4 represent the first examples of compounds with an N-heterocyclic carbene ligand coordinated to a low-valent uranium center. The paramagnetic complexes 1, 2, and 4 were characterized by (1)H NMR, UV-vis-NIR, and EPR spectroscopy as well as SQUID magnetization measurements and X-ray diffraction analyses. DFT studies indicate a significant degree of pi-bonding in the U(III)-carbene entity.
  • Castro-Rodriguez, I; H Nakai; P Gantzel; LN Zakharov; AL Rheingold; K Meyer
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY AMER CHEMICAL SOC 125 (51) 15734 - 15735 0002-7863 2003/12 [Refereed]
  • H Nakai; YJ Tang; P Gantzel; K Meyer
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY 1 (1) 24 - 25 1359-7345 2003 [Refereed]
     
    The synthesis and characterisation of a thallium(I) triscarbene complex of the chelating, tripodal carbene ligand 1,3,5-{tris(3-tert-butylimidazol-2-ylideno)methyl}-2,4,6-trimethylbenzene is reported, in which the thallium ion is coordinated by three N-heterocyclic carbene donors in a distorted trigonal planar environment.
  • H Nakai; S Ogo; Y Watanabe
    ORGANOMETALLICS AMER CHEMICAL SOC 21 (8) 1674 - 1678 0276-7333 2002/04 [Refereed]
     
    This paper reports on the first example of pH-dependent cross-coupling reactions of watersoluble organic halides (3-X(C6H4)CO2H, where X = Cl, Br, I) with organoboron compounds (PhB(OH)(2) and Ph4BNa) to form 3-Ph(C6H4)CO2H, catalyzed by the mononuclear organometallic aqua complex [(SCS)Pd-II(H2O)](2)(SO4) (1)(2)(SO4), SCS = C6H3-2,6-(CH2SBut)(2)) in basic media (8 < PH < 13, NaHCO3/NaOH buffers). The structure of 1(PF6) was unequivocally determined by X-ray analysis. The reactions show unique PH selectivity depending upon the organoboron compounds; i.e., the rate of the reactions with PhB(OH)2 shows a sharp maximum around PH 10, though the rate of the reactions with Ph4BNa shows a flat maximum in a PH range of about 8-11. The PH dependence is discussed on the basis of the pK(a), values of [1](2)(SO4) and PhB(OH)(2).
  • S Ogo; H Nakai; Y Watanabe
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY AMER CHEMICAL SOC 124 (4) 597 - 601 0002-7863 2002/01 [Refereed]
     
    This paper reports a pH-dependent H-2-activation {H-2 (pH 1-4) --> H+ + H- (pH -1) --> 2H(+) + 2e(-)} promoted by Cp*Ir complexes {Cp* = eta(5)-C-5(CH3)(5)}. In a pH range of about 1-4, an aqueous HNO3 solution of [Cp*Ir-III(H2O)(3)](2+) (1) reacts with 3 equiv of H-2 to yield a solution of [(Cp*Ir-III)(2)(mu-H)(3)](+) (2) as a result of heterolytic H-2-activation {2[1] + 3H(2) (pH 1-4) --> [2] + 3H(+) + 6H(2)O}. The hydrido ligands of 2 display protonic behavior and undergo H/D exchange with D+: [M-(H)(3)-M](+) + 3D(+) reversible arrow [M-(D)(3)-M](+) + 3H(+) (where M = Cp*Ir). Complex 2 is insoluble in a pH range of about -0.2 (1.6 M HNO3/H2O) to -0.8 (6.3 M HNO3/H2O). At pH -1 (10 M HNO3/H2O), a powder of 2 drastically reacts with HNO3 to give a solution of [Cp*Ir-III(NO3)(2)] (3) with evolution of H-2, NO, and NO2 gases. D-labeling experiments show that the evolved H-2 is derived from the hydrido ligands of 2. These results suggest that oxidation of the hydrido ligands of 2 {[2] + 4NO(3)(-) (pH -1) --> 2[3] + H-2 + H+ + 4e(-)} couples to reduction of NO3- (NO3- --> NO2- --> NO). To complete the reaction cycle, complex 3 is transformed into 1 by increasing the pH of the solution from -1 to 1. Therefore, we are able to repeat the reaction cycle using 1, H-2, and a pH gradient between 1 and -1. A conceivable mechanism for the H-2-activation cycle with reduction of NO3- is proposed.
  • H Fujihara; H Nakai
    LANGMUIR AMER CHEMICAL SOC 17 (21) 6393 - 6395 0743-7463 2001/10 [Refereed]
     
    This paper reports the preparation and characteristic property of a new nanocomposite gold cluster with fullerene as a carbon nanocluster, C-60-Au nanoparticles, together wit h the first account of electrochemical comparison of the C-60-Au nanoparticle films and the self-assembled monolayers of C-60-thiol 1 on gold electrodes. Octanethiol-stabilized gold nanoparticles were treated with a fullerene C-60-terminated alkanethiol. (1) to give new fullerenethiol-functionalized gold nanoparticles (C-60-Au nanoparticles) of 2 nm diameter with a very narrow size distribution. Immersion of a gold electrode in a solution of C-60-Au nanoparticles deposited the colloid films of them on the electrode surface which showed two distinct reversible reduction/oxidation waves and significant electrochemical stability. The C-60-Au nanoparticle films were firmly immobilized on the planar electrode by a simple self-assembly method without use of terminal ligand like bifunctional aminosiloxane or mercaptosiloxane. The electrochemical responses for the C60-Au nanoparticle films and self-assembled monolayers of C-60-thiol 1 adsorbed on gold electrodes are significantly different.
  • H Nakai; H Fujihara
    JOURNAL OF ORGANOMETALLIC CHEMISTRY ELSEVIER SCIENCE SA 611 (1-2) 566 - 569 0022-328X 2000/10 [Refereed]
     
    The preparation and properties of the self-assembled monolayers with oligo-ethyleneoxy linkages on flat and curved gold surfaces have been described. The electrochemical properties of the self-assembled monolayers of a tetrathiafulvalenyl-alkane monothiol and the ether-substituted alkane monothiol adsorbed onto gold electrodes showed no difference in their redox potentials and surface coverages. In contrast, the difference between the alkyl chain and the oxy-alkyl chain in the redox potentials and surface coverages was found in the self-assembled monolayers of the tetrathiafulvalenyl-tetrathiol and the ether-substituted tetrathiol adsorbed onto gold electrodes. The reaction of a thiol bearing oligo-ethyleneoxy linkages with octanethiolate-stabilized gold clusters gave the new oxy-Au clusters containing ether linkages which were dissolved in nonpolar and polar solvents. (C) 2000 Elsevier Science S.A. All rights reserved.
  • NAKAI Hidetaka; WATANABE Katsuhiko; ITO Seishiro; YOSHIHARA Masakuni; FUJIHARA Hisashi
    Journal of the Japan Society of Colour Material 一般社団法人 色材協会 73 (7) 325 - 329 0010-180X 2000/07 [Refereed]
     
    Tetrathiafulvalenyl-thiol (1), disulfide (2), thioacetate (3), and sulfide (4) have been prepared. The redox behaviors of the tetrathiafulvalene derivatives (1-3) depended on the nature of an electrolyte and a solvent used. Though a difference of electrochemical behavior between 1 and 2 was found in the cyclic voltammograms, the self-assembled monolayers (SAMs) from 1 and 2 showed the similar redox behaviors, while, 4 did not form SAM on a gold (Au) electrode.
  • NAKAI Hidetaka; TSUCHIYA Youichi; WATANABE Katsuhiko; MATSUSHITA Tsuyoshi; ITO Seishiro; YOSHIHARA Masakuni; FUJIHARA Hisashi
    Journal of the Japan Society of Colour Material 一般社団法人 色材協会 73 (4) 176 - 181 0010-180X 2000/04 [Refereed]
     
    The electrochemical property of alkane-tetrathiol or alkane-tetrapyrrole containing tetrathiafulvalene (TTF) and a new type of electropolymerization using the TTF-derivatized tetrathiol are described. Glassy carbon and gold electrodes have been modified by electropolymerization of the TTF-derived tetrathiol. The polymer films of the TTF-tetrathiol immobilized on glassy carbon and gold electrodes are remarkably stable to electrochemical recycling. The electrochemical behavior and the redox potentials of the polymer films of the TTF-tetrathiol depend on the nature of the counter anion of electrolyte or solvent. In contrast, the corresponding TTF-monothiol and TTF-tetrasulfide do not form the polymer films. The electrochemical property of the TTF-tetrathiol has been compared with that of the corresponding TTF-tetrapyrrole.
  • H Nakai; M Yoshihara; H Fujihara
    ELECTROCHEMISTRY ELECTROCHEMICAL SOC JAPAN 68 (1) 8 - 10 1344-3542 2000/01 [Refereed]
     
    The electrochemical properties of the self-assembled monolayers of a tetrathiafulvalenyl-alkane monothiol (1) and the etcher-substituted alkane monothiol (1-0) adsorbed onto gold electrodes showed no difference in their redox potentials and surface coverages. In contrast, the difference between the alkyl chain and the oxy-alkyl chain in the redox potentials and surface coverages was found in the self-assembled monolayers and the electropolymerized films of the tetrathiafulvalenyl-tetrathiol (2) and the ether-substituted tetrathiol (2-0) adsorbed onto gold electrodes.
  • H Nakai; M Yoshihara; H Fujihara
    LANGMUIR AMER CHEMICAL SOC 15 (25) 8574 - 8576 0743-7463 1999/12 [Refereed]
     
    New electroactive gold nanoparticles containing tetrathiafulvalene (TTF-Au nanoparticles) of 2-4 nm diameter have been prepared by the reaction of octanethiol-derivatized gold nanoparticles with a tetrathiafulvalenyl monothiol. Immersion of a gold electrode in a solution of the colloidal TTF-Au nanoparticles deposited the colloid films of them on the electrode surface which were remarkably stable under repeated electrochemical cycling. Thus, the TTF-Au nanoparticle films were firmly immobilized on the electrode by a simple self-assembly method without use of a terminal ligand like bifunctional aminosiloxane or mercaptosiloxane. A three-dimensional network of TTF-Au nanoparticles cross-linked by tetrathiafulvalenyl tetrathiol was assembled on a gold electrode.
  • H Fujihara; H Nakai; M Yoshihara; T Maeshima
    CHEMICAL COMMUNICATIONS ROYAL SOC CHEMISTRY (8) 737 - 738 1359-7345 1999/04 [Refereed]
     
    Remarkably stable self-assembled monolayer and polymer films composed of a new tetrathiafulvalenyl-tetrathiol have been formed on metal electrodes: this is a new class of surface modification by self-assembly and electrochemical polymerization using the same alkane-tetrathiol.

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