松尾　司 （マツオ　ツカサ）

コミュニケーション情報 byコメンテータガイド

• コメント

  元素の本質的特性に基づく物質創製と物質変換に取り組んでいます。ケイ素やホウ素などの典型元素化合物や鉄磁性錯体の設計と合成、遷移金属を用いた小分子の活性化について研究しています。

研究者情報

学位

• 博士（理学）（1999年03月 筑波大学）

ホームページURL

https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201101014458823852

科研費研究者番号

• 90312800

J-Global ID

• 201101014458823852

プロフィール

• 1970年 北海道遠軽町にて生まれる
  1989年 北海道立北見北斗高校 卒業
  1994年 東北大学理学部化学科 卒業（指導教官 櫻井 英樹 教授）
  1996年 東北大学大学院理学研究科化学専攻博士課程前期課程 修了（指導教官 吉良 満夫 教授）
  1999年 筑波大学大学院博士課程化学研究科 修了（指導教官 関口 章 教授）
  1999年 博士（理学）取得
  1999年 日本学術振興会 特別研究員(PD)
  1999年 筑波大学先端学際領域研究センター（化学系）助手
  2001年 分子科学研究所錯体化学実験施設 助手（川口グループ 川口 博之 助教授）
  2007年 理化学研究所フロンティア研究システム機能性有機元素化学特別研究ユニット 副特別研究ユニットリーダー
  2008年 理化学研究所基幹研究所機能性有機元素化学特別研究ユニット 副ユニットリーダー（玉尾 皓平 ユニットリーダー）
  2011年〜2014年 科学技術振興機構さきがけ研究員
  2012年 近畿大学理工学部応用化学科 准教授（応用元素化学研究室主宰）

  
  

  2020年 近畿大学理工学部応用化学科 教授
  現在に至る

研究キーワード

• パイ共役電子系   典型元素化学   高周期元素不飽和結合   磁性材料   機能性物質科学   機能性有機元素化合物   立体保護基   有機金属化学   有機ホウ素化学   有機元素化学   有機ケイ素化学   シロキサン   窒素分子   π電子系   4族遷移金属錯体   ヒドリド錯体   均一系触媒   反芳香族性   ハフニウム   4族遷移金属   カチオン性錯体   メタン   キレート効果   小分子活性化   ジアニオン   トランスメタル化   π電子系化合物   遷移金属錯体   かご型化合物   チタン   アリールオキシド配位子   一酸化炭素   リチウム   シクロブタジエンジアニオン   フェノキシド配位子   シクロブタジエン   ケイ素   芳香族性   ジルコニウム   二酸化炭素   

現在の研究分野（キーワード）

元素の本質的特性に基づく物質創製と物質変換に取り組んでいます。ケイ素やホウ素などの典型元素化合物や鉄磁性錯体の設計と合成、遷移金属を用いた小分子の活性化について研究しています。

研究分野

• ナノテク・材料 / 機能物性化学
• ライフサイエンス / 生物有機化学
• ナノテク・材料 / 構造有機化学、物理有機化学
• ナノテク・材料 / 無機・錯体化学

経歴

• 2022年10月 - 現在  近畿大学理工学部応用化学科 学科長
• 2020年04月 - 現在  近畿大学理工学部応用化学科教授
• 2011年10月 - 2015年03月  JSTさきがけ研究員
• 2012年04月  近畿大学理工学部応用化学科准教授
• 2008年04月 - 2012年03月  独立行政法人理化学研究所基幹研究所 機能性有機元素化学特別研究ユニット副ユニットリーダー
• 2007年04月 - 2008年03月  独立行政法人理化学研究所フロンティア研究システム 機能性有機元素化学特別研究ユニット副特別研究ユニットリーダー
• 2004年04月 - 2007年03月  自然科学研究機構 分子科学研究所 錯体化学実験施設助手
• 2001年04月 - 2004年03月  岡崎国立共同研究機構 分子科学研究所 錯体化学実験施設助手
• 1999年06月 - 2001年03月  筑波大学 先端学際領域研究センター（化学系）助手
• 1999年04月 - 1999年05月  日本学術振興会特別研究員（PD）

所属学協会

• 触媒学会   錯体化学会   有機合成化学協会   近畿化学協会   ケイ素化学協会   アメリカ化学会   日本化学会   

研究活動情報

論文

• A Series of Lithium Complexes of Bulky Rind-based Arylthiolate Ligands: Synthesis, Characterization, and Crystal Structures

  Masahiro Hamura; Kohei Sugano; Ryo Matsukura; Kei Ota; Tsukasa Nakahodo; Daisuke Hashizume; Tsukasa Matsuo

  Chemistry Letters 52 3 140 - 143 2023年03月 

  The bulky Rind-based thiols, (Rind)SH (1) [Rind = 1,1,7,7-tetra-R1-3,3,5,5-tetra-R2-s-hydrindacen-4-yl: EMind (a: R1 = Et, R2 = Me), Eind (b: R1 = R2 = Et), and MPhind (c: R1 = Me, R2 = Ph)], reacted with nBuLi in THF to afford a series of lithium arylthiolates, [(Rind)SLi]n(THF)m (2), whose structures were confirmed by an X-ray diffraction analysis. In the solid state, while the less bulky EMind-based lithium thiolate exhibited a linear dimer, [(EMind)SLi]2(THF)4 (2a), or trimer, [(EMind)SLi]3(THF)5 (2a′), the monomeric structures of (Eind)SLi(THF)3 (2b) and (MPhind)SLi(THF)2 (2c) were found for the bulky Eind- and the bulkier MPhind-based systems. The salt metathesis reaction between 2a and FeCl2(THF)1.5 in THF produced the anionic three-coordinate planar Fe(II) thiolate complex, [Li(THF)3][{(EMind)S}3Fe] (3a).
• Lewis Base Adducts of Phosphine-Stabilized Pb(II) Cations: Synthesis and Catalytic Hydroamination of Alkynes

  Aswin Chandran; José Miguel Léon Baeza; Vladislava Timofeeva; Raphael Nougué; Shintaro Takahashi; Ryoma Ohno; Antoine Baceiredo; Rene Segundo Rojas Guerrero; Mikhail Syroeshkin; Tsukasa Matsuo; Nathalie Saffon-Merceron; Tsuyoshi Kato

  Inorganic Chemistry 2022年09月 

  Phosphine-stabilized Pb(II) cations, generated by chloride abstraction from chloroplumbylene 1, readily react with Lewis bases (L) such as phosphines and amines to give the corresponding donor–acceptor complexes 3. These complexes 3 react with phenylacetlylene via alkyne insertion into the Pb–L bond to afford the corresponding vinylplumbylenes 4. Of particular interest, the stable complex 4-HNiPr2 (with a secondary amine) can be used as a hydroamination catalyst of phenylacetylene.
• Formation and Reactions of Ge=O Double-bonded Species Bearing EMind Groups

  Airi Kuroda; Naoko Fujita; Tomomi Horita; Kei Ota; Alfredo Rosas-Sánchez; Manabu Hoshino; Daisuke Hashizume; Tsukasa Matsuo

  Chemistry Letters 51 8 828 - 831 2022年08月 

  The reaction of the bulky EMind-based diarylgermylene, (EMind)2Ge: (1a) (EMind = 1,1,7,7-tetraethyl-3,3,5,5-tetramethyl-s-hydrindacen-4-yl), with pyridine N-oxide (Py+–O−) initially formed the Py-coordinated diarylgermanone, (EMind)2Ge(=O)(Py) (3a), which gradually converted to the 1,3,2,4-dioxadigermetane, (EMind)4Ge2(μ-O)2 (4a), through the dimerization of the germanone, (EMind)2Ge=O (2a). The Ge=O double-bond in 3a reacted not only with H2O to give the germanediol, (EMind)2Ge(OH)2 (5a), but also with Py+–O− to form the germanol, (EMind)2Ge(C5H4NO)(OH) (6a), via activation of the ortho C–H bond.
• A series of (E)-1,2-diaryldigermenes incorporating bulky Eind groups: structural characteristics and absorption properties

  Shogo Yagura; Naoki Hayakawa; Airi Kuroda; Kei Ota; Rhota Tanishita; Genya Urasaki; Tsukasa Nakahodo; Hidetaka Nakai; Manabu Hoshino; Daisuke Hashizume; Tsukasa Matsuo

  Dalton Transactions 51 48 18633 - 18641 2022年 

  A series of (E)-1,2-diaryldigermenes, (Eind)ArGe[double bond, length as m-dash]GeAr(Eind) [Ar = phenyl (2), thiophen-2-yl (3), 9,9-dimethyl-2-fluorenyl (4) and 2,2′-bithiophen-5-yl (5)], supported by the fused-ring bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups, have been obtained as yellow-orange to red crystalline solids by the reaction of 1,2-dibromodigermene, (Eind)BrGe[double bond, length as m-dash]GeBr(Eind) (1), with ArLi. In the crystals of 2–5, the digermene cores show a flexible nature adopting a trans-bent geometry with the trans-bent angles (θ) between the Ge–Ge vector and the CEind–Ge–CAr plane of 34.04(12)° (2), 38.3(3)° and 38.8(3)° (3), 33.69(12)° (4) and 39.30(13)° (5). In the UV-vis spectra, strong π–π* absorptions have been observed with an absorption maximum at 451 nm (ε = 1.3 × 104) (2), 455 nm (ε = 9.7 × 103) (3), 480 nm (ε = 1.3 × 104) (4) and 497 nm (ε = 1.4 × 104) (5), retaining the Ge[double bond, length as m-dash]Ge double bond in solution. The absorption data and DFT calculations provide evidence for the intrinsic π-conjugation between the Ge[double bond, length as m-dash]Ge chromophore and aromatic rings involving the narrowing of the HOMO–LUMO gaps (ΔE) with the extension of the carbon π-electron systems.
• Synthesis and Characterization of a Series of Diarylgermylenes and Dihalodigermenes Having Fused-Ring Bulky “Rind” Groups

  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 94 7 1931 - 1939 2021年07月 

  A series of diarylgermylenes, (Rind)2Ge: (1) [Rind = EMind (a), Eind (b), and MPind (c)], bearing the fused-ring bulky 1,1,3,3,5,5,7,7-octa-R-s-hydrindacen-4-yl (Rind) groups has been obtained as purple to blue crystals by the reaction of GeCl2·dioxane with 2 equiv. of (Rind)Li. A similar reaction using 1 equiv. of (Rind)Li affords the 1,2-dibromodigermenes, (Rind)BrGe=GeBr(Rind) (2) [Rind = Eind (b) and MPind (c)], as yellow to orange crystals. The ligand redistribution reaction between 1 and GeCl2·dioxane in toluene leads to the formation of the 1,2-dichlorodigermenes, (Rind)ClGe=GeCl(Rind) (3) [Rind = EMind (a), Eind (b), and MPind (c)]. The molecular structures of 1a, 1c, 2c, and 3c have been newly determined by X-ray crystallographic analysis. The 1,2-dihalodigermenes, (Rind)XGe=GeX(Rind) [X = Br (2) and Cl (3)], show a dimeric form with a Ge=Ge double bond in the solid state, but exist as a monomeric halogermylene, (Rind)XGe: [X = Br (4) and Cl (5)], in solution. The electronic properties of the Rindbased diarylgermylenes, dihalodigermenes, and halogermylenes have been experimentally and theoretically investigated.
• A Series of Room-Temperature Thermally Stable Bromostannylenes Bearing the Bulky Rind Group: Synthesis, Characterization, and Crystal Structures

  Yasuyuki Numata; Yuri Nishikawa; Konan Inoue; Hiroaki Ohnishi; Shigeaki Konaka; Tomoharu Tanikawa; Daisuke Hashizume; Tsukasa Matsuo

  Organometallics 40 12 1956 - 1965 2021年06月 

  A series of bromostannylenes, (Rind)BrSn: (1; Rind = EMind (a, R1 = Et, R2 = Me), Eind (b, R1 = R2 = Et), MPind (c, R1 = Me, R2 = nPr)), have been obtained as room-temperature thermally stable crystalline materials incorporating the fused-ring bulky Rind groups (Rind = 1,1,7,7-tetra-R1-3,3,5,5-tetra-R2-s-hydrindacen-4-yl). The bulky Eind- and the bulkier MPind-based bromostannylenes (1b,c) have been synthesized by the reaction of SnBr2·(dioxane) with 1 equiv of (Rind)Li in THF. In contrast, the less bulky EMind-based halostannylenes (EMind)XSn: (X = Br (1a), Cl (2a)) have been prepared by a ligand redistribution reaction between the diarylstannylene (EMind)2Sn: (3a) and SnX2·(dioxane) (X = Br, Cl), in toluene. The crystal structures of (EMind)BrSn: (1a), (Eind)BrSn: (1b), and (MPind)BrSn: (1c) have been determined by X-ray diffraction methods along with that of (EMind)ClSn: (2a). While the bulkier MPind-based 1c has a monomeric structure with a bent two-coordinate Sn(II) center, a coordination dimer was found for the Eind-based 1b in which two Sn atoms are asymmetrically bridged by two Br atoms. The less bulky EMind-based 1a and 2a show a unique one-dimensional (1-D) polymeric structure in their crystals with alternating Sn and Br or Cl atoms supported by the perpendicularly oriented EMind groups. The halostannylenes 1a–c and 2a all exist as monomers in solution on the basis of their spectroscopic data, and their electronic properties have been experimentally and theoretically characterized.
• Products of [2+2] Cycloaddition between a W Si Triple-bonded Complex and Alkynes: Isolation, Structure, and Non-classical Bonding Interaction

  Takashi Yoshimoto; Hisako Hashimoto; Mausumi Ray; Naoki Hayakawa; Tsukasa Matsuo; Jaydeb Chakrabarti; Hiromi Tobita

  CHEMISTRY LETTERS 49 3 311 - 314 2020年03月 [査読有り]
   

  The reactions of a W Si triple-bonded complex, i.e. a silylyne complex, with alkynes gave [2+2] cycloaddition products, which are formally regarded as conjugated metallasilacyclobutadienes. X-ray crystallography and DFT calculations however revealed that the products have a non-planar W-Si-C-C four-membered metallacyclic linkage with a diagonal Si center dot center dot center dot C interaction.
• Comparison of the Chemical Bonding in (Eind)(2)Ge=E (E = O and S): Synthesis and Characterization of Germanethione Bearing Bulky Eind Groups

  Naoko Fujita; Liangchun Li; Nicolas Lentz; Shigeaki Konaka; Airi Kuroda; Ryoma Ohno; Naoki Hayakawa; Kohei Tamao; David Madec; Tsuyoshi Kato; Alfredo Rosas-Sanchez; Daisuke Hashizume; Tsukasa Matsuo

  CHEMISTRY LETTERS 49 2 141 - 144 2020年02月 [査読有り]
   

  A new diarylgermanethione, (Eind)(2)Ge=S, supported by the fused-ring bulky Eind groups (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) has been obtained as yellow-orange crystals by the direct reaction between the diarylgermylene, (Eind)(2)Ge:, and elemental sulfur in solution. The structure and bonding nature of the germanethione have been compared to those of its oxygen congener, germanone, (Eind)(2)Ge=O. We also report the X-ray structure analysis of the hydroxy(mercapto)germane, (Eind)(2)Ge(OH)(SH).
• Reaction of Dialumane Incorporating Bulky Eind Groups with Pyridines

  Takahiro Murosaki; Ryoma Ohno; Tomohiro Agou; Daisuke Hashizume; Tsukasa Matsuo

  Inorganics 7 129  2019年10月 [査読有り][招待有り]
  
• Synthesis and Thermal Reactions of a Spiro-type Cyclotrisilene Obtained from the Reaction between a Disilenide and a Base Adduct of a Bromosilylene

  Kosai Tomoyuki; Nishimura Shogo; Hayakawa Naoki; Matsuo Tsukasa; Iwamoto Takeaki

  CHEMISTRY LETTERS 48 9 1168 - 1170 2019年09月 [査読有り]
  
• Reactions of a Silylyne Complex with Aldehydes: Formation of W-Si-O-C Four-Membered Metallacycles and Their Metathesis-Like Fragmentation

  Takashi Yoshimoto; Hisako Hashimoto; Nozomi Takagi; Shigeyoshi Sakaki; Naoki Hayakawa; Tsukasa Matsuo; Hiromi Tobita

  CHEMISTRY-A EUROPEAN JOURNAL 25 15 3795 - 3798 2019年03月 [査読有り]
   

  A tungsten silylyne complex having a WSi triple bond reacted with two molecules of aldehydes at room temperature to give W-Si-O-C four-membered metallacycles by [2+2] cycloaddition and subsequent formyl hydrogen transfer from one aldehyde molecule to another. Upon heating to 70 degrees C, the four-membered metallacycles underwent metathesis-like fragmentation cleanly to afford carbyne complexes and silanoic esters, in a manner similar to that of metallacyclobutadiene, an intermediate of alkyne metathesis reactions, and dimerization of the latter products gave 1,3-cyclodisiloxanes. The silanoic ester was also trapped by pivalaldehyde to give a [2+2] cycloaddition product in high yield.
• π-Electron systems containing Si=Si double bonds

  Tsukasa Matsuo; Naoki Hayakawa

  Science and Technology of Advanced Materials 19 1 108 - 129 2018年12月 [査読有り]
   

  Sterically large substituents can provide kinetic stabilization to various types of low-coordinate compounds. For example, regarding the chemistry of the group 14 elements, since West et al. introduced the concept of kinetic protection of the otherwise highly reactive Si=Si double bond by bulky mesityl (2,4,6-trimethylphenyl) groups in 1981, a number of unsaturated compounds of silicon and its group homologs have been successfully isolated by steric effects using the appropriate large substituents. However, the functions and applications of the Si–Si π-bonds consisting of the 3pπ electrons on the formally sp2-hybridized silicon atoms have rarely been explored until 10 years ago, when Scheschkewitz and Tamao independently reported the model systems of the oligo(p-phenylenedisilenylene)s (Si–OPVs) in 2007. This review focuses on the recent advances in the chemistry of π-electron systems containing Si=Si double bonds, mainly published in the last decade. The synthesis, characterization, and potential application of a variety of donor-free π-conjugated disilene compounds are described.
• A stable free tetragermacyclobutadiene incorporating fused-ring bulky EMind groups

  Katsunori Suzuki; Yasuyuki Numata; Naoko Fujita; Naoki Hayakawa; Tomoharu Tanikawa; Daisuke Hashizume; Kohei Tamao; Hiroyuki Fueno; Kazuyoshi Tanaka; Tsukasa Matsuo

  CHEMICAL COMMUNICATIONS 54 18 2200 - 2203 2018年03月 [査読有り]
   

  The first free cyclobutadiene (CBD) germanium analogue was obtained as room-temperature stable dark red crystals via the reaction of the bulky EMind-substituted 1,2-dichlorodigermene with lithium naphthalenide. The cyclic 4-electron antiaromaticity is essentially stabilized by the polar Jahn-Teller distortion in the germanium CBD producing a planar rhombic-shaped charge-separated structure.
• Synthesis and characterization of N-heterocyclic carbene-coordinated silicon compounds bearing a fused-ring bulky Eind group

  Naoki Hayakawa; Kazuya Sadamori; Shinsuke Mizutani; Tomohiro Agou; Tomohiro Sugahara; Takahiro Sasamori; Norihiro Tokitoh; Daisuke Hashizume; Tsukasa Matsuo

  Inorganics 6 1 2018年03月 [査読有り]
   

  The reactions of the fused-ring bulky Eind-substituted 1,2-dibromodisilene, (Eind)BrSi=SiBr(Eind) (1a) (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (a)), with N-heterocyclic carbenes (NHCs) (Im-Me4 = 1,3,4,5-tetramethylimidazol-2-ylidene and Im-iPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) are reported. While the reaction of 1a with the sterically more demanding Im-iPr2Me2 led to the formation of the mono-NHC adduct of arylbromosilylene, (Im-iPr2Me2)→SiBr(Eind) (2a'), a similar reaction using the less bulky Im-Me4 affords the bis-NHC adduct of formal arylsilyliumylidene cation, [(Im-Me4)2→Si(Eind)]+[Br-] (3a). The NHC adducts 2a' and 3a can also be prepared by the dehydrobromination of Eind-substituted dibromohydrosilane, (Eind)SiHBr2 (4a), with NHCs. The NHC-coordinated silicon compounds have been characterized by spectroscopic methods. The molecular structures of bis-NHC adduct, [(Im-iPr2Me2)2→Si(Eind)]+[Br-] (3a'), and 4a have been determined by X-ray crystallography.
• π-Conjugation between a Si=Si Double Bond and Thiophene Rings: Synthesis, Structural Characteristics, and Photophysical Properties of 1,2-Bis(thiophen-2-yl)disilene and 1,2-Bis(2,2'-bithiophene-5-yl)disilene

  Hayakawa Naoki; Nishimura Shogo; Kazusa Nobuhiro; Shintani Nozomu; Nakahodo Tsukasa; Fujihara Hisashi; Hoshino Manabu; Hashizume Daisuke; Matsuo Tsukasa

  Organometallics 36 17 3226 - 3233 2017年09月 [査読有り]
   

  The two new disilene compounds, 1,2-bis-(thiophen-2-yl)disilene (1) and 1,2-bis(2,2'-bithiophen-5-yl)disilene (2), supported by the fused-ring bulky Eind groups (Eind = 1,1,3,3,5,S,7,7-octaethyl-s-hydrindacen-4-yl) have been obtained as orange and purple crystals, respectively, by the reduction of the corresponding dibromosilanes. Their X-ray structures and spectroscopic properties demonstrate the effective pi-conjugation between a Si=Si double bond and thiophene units. Notably, the pi-extended 2 exhibits a distinct emission both in solution and in the solid state at room temperature based on the essentially coplanar 1,2-bis-(bithienyl)disilene skeleton. The structural features and electronic properties of 1 and 2 have been thoroughly characterized both experimentally and computationally.
• Thermally Stable Monosubstituted Thiophene 1-Oxide and 1-Imides Stabilized by a Bulky Rind Group at Their 3-Position: Synthesis, Structure, and Inversion Barriers on the Sulfur Atom

  Takashi Otani; Mayu Miyoshi; Takanori Shibata; Tsukasa Matsuo; Daisuke Hashizume; Kohei Tamao

  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 90 6 697 - 705 2017年06月 [査読有り]
   

  The synthesis and characterization of thermally stable monosubstituted thiophene 1-oxide and 1-imides stabilized by EMind (1,1,7,7-tetraethyl-3,3,5,5-tetramethyl-s-hydrindacen-4yl) group on the 3-position are described. In addition to the molecular structures determined by X-ray crystallography, inversion barriers at the three-coordinated sulfur atoms have been determined by a coalescence method using diastereotopic C-3 and C-5 indacene carbon atoms as a (CNMR)-C-13 probe.
• Cleavage of a P=P Double Bond Mediated by N-Heterocyclic Carbenes

  Naoki Hayakawa; Kazuya Sadamori; Shota Tsujimoto; Miho Hatanaka; Tomonari Wakabayashi; Tsukasa Matsuo

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 56 21 5765 - 5769 2017年05月 [査読有り]
   

  The reaction of the bulky diphosphenes (Rind) P=P(Rind) (1; Rind = 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl) with two molecules of N-heterocyclic carbene (NHC; 1,3,4,5-tetramethylimidazol-2-ylidene) resulted in the quantitative formation of the NHC-bound phosphinidenes NHC -> P(Rind) (2), along with the cleavage of the P=P double bond. The reaction times are dependent on the steric size of the Rind groups (11 days for 2a (R=Et) and 2 h for 2b (R=Et, Me) at room temperature). The mechanism for the double bond-breaking is proposed to proceed via the formation of the NHC-coordinated, highly polarized diphospehenes 3 as an intermediate. Approach of a second NHC to 3 induces P-P bond cleavage and P-C bond formation, which proceeds through a transition state with a large negative Gibbs energy change to afford the two molecules of 2, thus being the rate-determining step of the overall reaction with the activation barriers of 80.4 for 2a and 29.1 kJ mol(-1) for 2b.
• 1,2-Dihalodigermenes bearing bulky Eind groups: Synthesis, characterization, and conversion to halogermylenoids

  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 47 3 814 - 822 2017年 [査読有り]
   

  1,2-Dihalodigermenes, (E)-(Eind)XGeGeX(Eind) (X = Br and Cl), bearing the fused-ring bulky Eind group (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) have been isolated as orange-yellow crystals by the ligand redistribution reaction between the diarylgermylene, (Eind)2Ge:, and GeX2·dioxane in toluene via the cleavage and recombination of the Ge-C and Ge-X bonds. The dihalodigermenes have a GeGe double bond character in the crystalline state, but dissociate into halogermylenes, (Eind)XGe:, in solution. The addition of excess LiBr to the THF solution of the bromogermylene, (Eind)BrGe:, led to the formation of an equilibrium mixture containing the lithium bromogermylenoid, [Li+][(Eind)GeBr2]-. The bromogermylenoid can be isolated as a cryptand-separated potassium ion pair, [K+(crypt-222)][(Eind)GeBr2]-, which has been structurally characterized.
• A Square-Planar Complex of Platinum(0)

  Katsuhiko Takeuchi; Hiro-omi Taguchi; Ippei Tanigawa; Shota Tsujimoto; Tsukasa Matsuo; Hiromasa Tanaka; Kazunari Yoshizawa; Fumiyuki Ozawa

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 55 49 15347 - 15350 2016年12月 [査読有り]
   

  The Pt-0 complex [Pt(PPh3)(Eind(2)-BPEP)] with a pyridine-based PNP-pincer-type phosphaalkene ligand (Eind(2)-BPEP) has a highly planar geometry around Pt with Sigma(Pt)=358.6 degrees. This coordination geometry is very uncommon for formal d(10) complexes, and the Pd and Ni homologues with the same ligands adopt distorted tetrahedral geometries. DFT calculations reveal that both the Pt and Pd complexes are M-0 species with nearly ten valence electrons on the metals whereas their atomic orbital occupancies are evidently different from one another. The Pt complex has a higher occupancy of the atomic 6s orbital because of strong s-d hybridization due to relativistic effects, thereby adopting a highly planar geometry reflecting the shape and orientation of the partially unoccupied dx2-y2 orbital.
• Activation of Dihydrogen by Masked Doubly Bonded Aluminum Species

  Koichi Nagata; Takahiro Murosaki; Tomohiro Agou; Takahiro Sasamori; Tsukasa Matsuo; Norihiro Tokitoh

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 55 41 12877 - 12880 2016年10月 [査読有り]
   

  Activation of dihydrogen by masked dialumenes (Al=Al doubly bonded species) is reported. Reactions of barrelene-type dialumanes, which have the reactivity as masked equivalents of 1,2-diaryldialumenes ArAl=AlAr, with H-2 afforded dihydroalumanes ArAlH2 at room temperature (Ar: bulky aryl groups). These dihydroalumanes form hydrogen-bridged dimers [ArHAl(-H)](2) in the crystalline state, while a monomer-dimer equilibrium was suggested in solution. The 1,2-diaryldialumenes generated from the barrelene-type dialumanes are the putative active species in the cleavage of H-2.
• A Silylyne Tungsten Complex Having an Eind Group on Silicon: Its Dimer-Monomer Equilibrium and Cycloaddition Reactions with Carbodiimide and Diaryl Ketones

  Takashi Yoshimoto; Hisako Hashimoto; Naoki Hayakawa; Tsukasa Matsuo; Hiromi Tobita

  ORGANOMETALLICS 35 20 3444 - 3447 2016年10月 [査読有り]
   

  A tungsten silylyne complex having a fused-ring group (Eind) on Si was synthesized from a hydrido hydrosilylene complex via stepwise abstraction of a proton and a hydride and was isolated as an eight-membered cyclic dimer bound through two isocarbonyl linkages. The IR and variable-temperature NMR analyses revealed that the dimer is in equilibrium with a monomeric silylyne complex in solution. The silylyne complex underwent [2 + 2] cycoaddition reactions with carbodiimide and diaryl ketones, and in the latter case the cycloaddition product further reacted with another molecule of ketone to give a complex formed through C-C and Si-C coupling.
• Synthesis and Structural Characteristics of Discrete Organoboron and Organoaluminum Hydrides Incorporating Bulky Eind Groups

  Takahiro Murosaki; Shohei Kaneda; Ryota Maruhashi; Kazuya Sadamori; Yoshiaki Shoji; Kohei Tamao; Daisuke Hashizume; Naoki Hayakawa; Tsukasa Matsuo

  ORGANOMETALLICS 35 19 3397 - 3405 2016年10月 [査読有り]
   

  The bulky Eind-based aryllithium, (Eind)Li (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl), reacted with BF3 center dot OEt2 in Et2O to form the corresponding aryl-difluoroborane (Eind)BF2 (1), along with a trace amount of the sterically congested diarylborane, (Eind)(2)BH (2). The reaction of 1 with LiAlH4 in THE led to the isolation of the corresponding lithium trihydroborate [Li(thf)](2)[(Eind)BH3](2) (3), which can be transformed into the diborane(6), (Eind)HB(mu-H)(2)BH(Eind) (4), with treatment with Me3SiCl. The Eind-based lithium trihydroaluminate [Li-(OEt2)](2)[(Eind)AlH3](2) (5) has been synthesized by the reaction of (Eind)Li with LiAlH4 in Et2O. The subsequent addition of Me3SiCl to a solution of 5 in toluene produced the dialumane(6), (Eind)HAl(mu-H)(2)AlH(Eind) (6), the heavier congener of 4. The dialumane(6) 6 reacted with lithium metal in a mixed solvent of Et20 and toluene to give the diarylalumane, (Eind)(2)AlH (7), via a disproportionation reaction along with the cleavage and recombination of the Al-C. bond. The discrete monomeric structures of 1, 2, and 7 and dimeric structures of 3, 4, 5, and 6 have been determined by X-ray crystallography.
• Synthesis and Structural Characterization of Lithium and Titanium Complexes Bearing a Bulky Aryloxide Ligand Based on a Rigid Fused-Ring s-Hydrindacene Skeleton

  Shoya Kanazawa; Taishi Ohira; Shun Goda; Naoki Hayakawa; Tomoharu Tanikawa; Daisuke Hashizume; Yutaka Ishida; Hiroyuki Kawaguchi; Tsukasa Matsuo

  INORGANIC CHEMISTRY 55 13 6643 - 6652 2016年07月 [査読有り]
   

  The bulky aryl alcohols, (Rind)OH (1) [Rind = EMind (a) and Eind (b)], based on the rigid fused-ring 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacene skeleton were prepared by the reaction of (Rind)Li with nitrobenzene followed by protonation. The treatment of 1 with (BuLi)-Bu-n affords the lithium aryloxide dimers [(Rind)OLi(THF)](2) (2) or trimers [(Rind)OLi](3) (3), depending on the employed solvents (THF = tetrahydrofuran). The salt metathesis reaction of [(EMind)OLi(THF)](2) (2a) with TiCl4(THF)(2) leads to the formation of the mononuclear diamagnetic mono- and bis(aryloxide) Ti(IV) complexes, [(EMind)O]TiCl3(THF) (4a) and [(EMind)O](2)TiCl2 (5a). We also isolated a trace amount of the tris(aryloxide) Ti(IV) complex, [(EMind)O](3)TiCl (6a). The reaction between 2a and TiCl3(THF)(3) resulted in the isolation of the mononuclear paramagnetic mono- and bis(aryloxide) Ti(III) complexes, [(EMind)O]TiCl2(THF)(2) (7a) and [(EMind)O](2)TiCl(THF)(2) (8a). The discrete monomeric structures of the titanium complexes 4a, 5a, 6a, 7a, and 8a were determined by X-ray crystallography.
• Synthesis and Magnetic Properties of Linear Two-coordinate Monomeric Diaryliron(II) Complexes Bearing Fused-ring Bulky "Rind" Groups

  Shun Goda; Masanori Nikai; Mikinao Ito; Daisuke Hashizume; Kohei Tamao; Atsushi Okazawa; Norimichi Kojima; Hiroyuki Fueno; Kazuyoshi Tanaka; Yoshio Kobayashi; Tsukasa Matsuo

  CHEMISTRY LETTERS 45 6 634 - 636 2016年06月 [査読有り]
   

  Monomeric diaryliron(Il) complexes, Fe(Rind)(2), have been obtained by introducing fused-ring bulky "Rind" groups. For Fe(Eind)(2), a significant orbital contribution of the Fe(II) ion due to the linear two-coordination has been determined by the highly effective magnetic moment (mu(eff) = 5.82 mu(B)) and the extraordinarily large internal hyperfine field (H-n = ca. 140 T) in the Mossbauer spectrum. Variable-frequency out-of-phase ac susceptibility data demonstrate an effective spin-reversal barrier of U-eff = 51.2(7) cm(-1) associated with the single-ion magnet behavior.
• Unsymmetrical PNP-Pincer Type Phosphaalkene Ligands Protected by a Fused-Ring Bulky Eind Group: Synthesis and Applications to Rh(I) and Ir(I) Complexes

  Hiro-omi Taguchi; Daichi Sasaki; Katsuhiko Takeuchi; Shota Tsujimoto; Tsukasa Matsuo; Hiromasa Tanaka; Kazunari Yoshizawa; Fumiyuki Ozawa

  ORGANOMETALLICS 35 10 1526 - 1533 2016年05月 [査読有り]
   

  We recently reported that 2-(phospholanylmethyl)-6-(2-phosphaethenyl)pyridine (PPEP) with a 2,4,6-tri-tert-butylphenyl group (Mes*) as steric protection of the P=C bond serves as a noninnocent ligand on leading to extremely high reactivity toward metal ligand cooperative activation of ammonia and acetonitrile. The high reactivity is largely due to the strong pi-accepting properties of the P=C bond. However, PPEP had a stability problem that provokes the loss of the P=C bond on other transition metals, including Rh(I), and restricts its utilization. This paper describes the synthesis of Eind-PPEP protected by an octaethyl-s-hydrindacen-4-yl group (Eind) instead of Mes*. The fused ring bulky Eind group successfully prevents the loss of the P=C bond and enables us to compare the reactivity of Rh(I) and Ir(I) complexes toward ammonia. The complex K[RhCl(Eind-PPEP*)], bearing a dearomatized Eind-PPEP* ligand, undergoes simple ligand displacement to give [Rh(NH3)(Eind-PPEP*)], whereas the iridium analogue K[IrCl(Eind-PPEP*)] causes N-H bond cleavage to form [Ir(NH2)(Eind-PPEP)]. DFT calculations indicate a thermodynamic cause of the metal-dependent product change.
• Synthesis and Structures of Sterically Congested Diarylsilanes Bearing Two Bulky Rind Groups

  Naoki Hayakawa; Tatsuto Morimoto; Akihiro Takagi; Tomoharu Tanikawa; Daisuke Hashizume; Tsukasa Matsuo

  CHEMISTRY LETTERS 45 4 409 - 411 2016年04月 [査読有り]
   

  The sterically overcrowded diarylsilanes, (Rind)(2)SiH2 and (Rind)(2)SiBr2, with the two bulky Rind groups (Rind: 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl) have been synthesized by the coupling reaction of the Rind-substituted monochlorosilanes, (Rind)SiH2Cl, with (Rind)Li followed by bromination of the Si-H bonds. The key intermediates, (Rind)SiH2Cl, have been obtained by the reactions of the trihydrosilanes, (Rind)SiH3, with trichloroisocyanuric acid. The structural features of (Rind)(2)SiH2 and (Rind)(2)SiBr2 have been fully characterized by NMR spectroscopy and X-ray diffraction studies.
• (Z)-1,2-Di(1-pyrenyl)disilene: Synthesis, Structure, and Intramolecular Charge-Transfer Emission

  Megumi Kobayashi; Naoki Hayakawa; Tsukasa Matsuo; Baolin Li; Takeo Fukunaga; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 3 758 - 761 2016年01月 [査読有り]
   

  (Z)-1,2-Di(1-pyrenyl)disilene containing bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups has been obtained as purple crystals by the reductive coupling reaction of the corresponding dibromosilane with lithium naphthalenide. An X-ray crystallographic analysis revealed an Eind- and pyrenyl-meshed molecular gear around the disilene core adopting the Z configuration, in which the two pyrenyl groups intramolecularly interact through the pi-pi stacking with a distance of 3.635 angstrom between the centers of the two pyrene rings. The disilene pi-system exhibits a pi(Si-Si) -> pi*(pyrene) intramolecular charge-transfer (ICT) fluorescence at room temperature, whose wavelengths depend on the solvent polarity. The photophysical properties are theoretically supported by computational studies including excited-state calculations.
• Coplanar Oligo(p-phenylenedisilenylene)s as Si=Si Analogues of Oligo(p-phenylenevinylene)s: Evidence for Extended pi-Conjugation through the Carbon and Silicon,pi-Frameworks

  Liangchun Li; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 47 15026 - 15035 2015年12月 [査読有り]
   

  A series of oligo(p-phenylenedisilenylene)s (Si-OPVs 1-4), silicon analogues of oligo(p-phenylenevinylene)s, up to the tetramer have been synthesized and isolated by the introduction of a newly developed protecting group [(HexO)MEind] for improving their solubility. The experimental and theoretical studies of the Si-OPVs 1-4 demonstrate the fully extended pi-conjugation of the Si-OPV main chains. Single crystal X-ray analyses of the monomer 1 and the dimer 2 revealed the highly coplanar Si-OPV backbones facilitating the effective extension of the 7r-conjugation, which has further been validated by the significant increases in the absorption maxima from 465 nm for the monomer 1 to 610 nm for the tetramer 4. The absorption maxima exhibit an excellent fit to Meier's equation, leading to the estimation of an effective conjugation length (ECL) of 9 repeat units (nEcL = 9) and the absorption maximum of 635 nm for the infinite chain (lambda(infinity) = 635 nm). In sharp contrast to other nonemissive disilenes, the Si-OPVs 2-4 show an intense fluorescence from 613 to 668 nm at room temperature with the quantum yields up to 0.48. All the data presented here provide the first evidence for the efficient extended pi-conjugation between the Si=Si double bonds and the carbon pi-electron systems over the entire Si-OPV skeleton. This study reveals the possibility for developing the conjugated disilene pi-systems, in which the Si=Si double bonds would be promising building blocks, significantly optimizing the intrinsic photophysical and electrochemical properties of the carbon-based pi-conjugated materials.
• Fused-Ring Bulky "Rind" Groups Producing New Possibilities in Elemento-Organic Chemistry

  Tsukasa Matsuo; Kohei Tamao

  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 88 9 1201 - 1220 2015年09月 [査読有り]
   

  Kinetic stabilization with sterically bulky substituents or ligands has played a pivotal role in exploring a large variety of unsaturated compounds or low-coordinated complexes. This article describes our findings that a series of fused-ring octa-R-substituted s-hydrindacenyl groups (Rind groups), which we developed since 2007, can act as unique protecting groups both in main group chemistry and in transition-metal chemistry. The synthesis, structures, and properties of various types of highly reactive unsaturated and low-coordinated element-organic compounds of Groups 1, 2, 8, 11, and 13-17 featuring the bulky Rind groups are covered.
• π-Conjugated Disilenes and Tetrasilacyclobutadiene

  Tsukasa Matsuo

  Chemical Science of Electron Systems 393 - 402 2015年01月 [査読有り]
   

  The kinetic stabilization using sterically demanding bulky substituents or ligands provides us an exciting opportunity to explore a large variety of organoelement unsaturated compounds. We recently demonstrated that a new class of fused-ring bulky octa-R-substituted s-hydrindacenyl groups (Rind groups) can act as unique protecting groups in the main group chemistry as well as in the transition metal chemistry. This manuscript describes the recent advances in the chemistry of π-conjugated systems containing sp2-hybridized silicon atoms stabilized by the bulky Rind groups. The synthesis and characterization of various π-conjugated disilene compounds as well as a planar rhombic charge-separated tetrasilacyclobutadiene incorporating the bulky Rind groups are covered.
• Extremely active alpha-olefin polymerization and copolymerization with ethylene catalyzed by a dMAO-activated zirconium(IV) dichloro complex having an [OSSO]-type ligand

  Tomoyuki Toda; Norio Nakata; Tsukasa Matsuo; Akihiko Ishii

  RSC ADVANCES 5 108 88826 - 88831 2015年 [査読有り]
   

  The ability of a zirconium(IV) dichloro complex (6b) incorporating an [OSSO]-type ligand 5 with dMAO as an activator for the polymerization of 1-hexene and 4-methyl-1-pentene (4-MP) is described. In the polymerization of 1-hexene, the combination of the 6b/dMAO catalyst system efficiently provided poly(1-hexene)s with completely isotactic [mmmm] pentad more than 95% and relatively large molecular weight (M-w = 40 000-150 000 g mol(-1)). The corresponding activity was recorded with quite high values up to 18 100 g mmol(6b)(-1) h(-1), which increased significantly compared with those of the related non-Cp complexes. The polymerization of 4-MP using the 6b/dMAO system at different temperatures also gave perfect isotactic poly(4-MP) s ([mmmm] > 95%) with moderate molecular weights (M-w = 7000-21 300 g mol(-1)), relatively narrow polydispersities (M-w/M-n = 1.5-1.7), and activities of 1220-1690 g mmol(6b)(-1) h(-1). This catalyst system was also found to promote ethylene copolymerization with different amounts of 1-hexene at 25 degrees C under atmospheric pressure producing random ethylene/1-hexene copolymers (M-w = 10 100-17 300 g mol(-1), M-w/M-n = 1.8-1.9, 1-hexene contents = 37.3-66.7 mol%) with fairly high activity up to 2700 g mmol(6b)(-1) h(-1).
• Synthesis and Characterization of Diphosphenes Bearing Fused-Ring Bulky Rind Groups

  Baolin Li; Shota Tsujimoto; Yongming Li; Hayato Tsuji; Kohei Tamao; Daisuke Hashizume; Tsukasa Matsuo

  HETEROATOM CHEMISTRY 25 6 612 - 618 2014年11月 [査読有り]
   

  Diphosphenes stabilized by the fused-ring bulky 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl (Rind) groups have been obtained as orange crystals by the reduction of the corresponding dichlorophosphines, (Rind)PCl2, with lithium naphthalenide (LiNaph). The molecular structures of (Eind) PCl2 and the diphosphenes, (Eind) P=P(Eind) and (EMind) P=P(EMind), having the bulky Eind and the less bulky EMind groups, have been confirmed by X-ray crystallography. The formation of the P=P bond has been fully characterized by spectroscopic methods. (C) 2014 Wiley Periodicals, Inc.
• An Isolable Diborane(4) Compound with Terminal B-H Bonds: Structural Characteristics and Electronic Properties

  Yoshiaki Shoji; Shohei Kaneda; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao; Daisuke Hashizume; Tsukasa Matsuo

  CHEMISTRY LETTERS 43 10 1587 - 1589 2014年10月 [査読有り]
   

  The first isolable diborane(4) containing terminal B-H bonds, protected by the bulky 1,1,7,7-tetramethyl-3,3,5,5-tetrapropyl-s-hydrindacen-4-yl (MPind) groups, was synthesized as air- and moisture-sensitive colorless crystals. The structure and bonding nature of this H-terminal diborane(4), characterized by X-ray crystallography, NMR studies, and DFT calculations, were compared to those of the previously reported isomer, a doubly H-bridged butterfly-shaped diborane(4) bearing the less bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Bind) groups. The two distinct structures of these dihydro-diborane(4) compounds may be primarily attributed to the intramolecular steric effects of the bulky protecting groups.
• Reactions of Diaryldibromodisilenes with N-Heterocyclic Carbenes: Formation of Formal Bis-NHC Adducts of Silyliumylidene Cations

  Tomohiro Agou; Naoki Hayakawa; Takahiro Sasamori; Tsukasa Matsuo; Daisuke Hashizume; Norihiro Tokitoh

  CHEMISTRY-A EUROPEAN JOURNAL 20 30 9246 - 9249 2014年07月 [査読有り]
   

  Reactions of stable 1,2-dibromodisilenes ((E)-Ar(Br) Si=Si(Br)Ar) with N-heterocyclic carbenes (NHC) afforded NHC-arylbromosilylene adducts or bromide salts of the corresponding bis-NHC adducts of the formal arylsilyliumylidene cations ([ArSi:](+)). In some cases, an NHC was able to replace a bromide anion in the coordination sphere of the arylbromosilylene-NHC adduct.
• Highly Coplanar (E)-1,2-Di(1-naphthyl)disilene Involving a Distinct CH-pi Interaction with the Perpendicularly Oriented Protecting Eind Group

  Megumi Kobayashi; Naoki Hayakawa; Koichi Nakabayashi; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  CHEMISTRY LETTERS 43 4 432 - 434 2014年04月 [査読有り]
   

  An air-stable emissive di(1-naphthyl)disilene protected by the bulky Eind groups (Eind: 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) has been obtained by reducing the corresponding dibromosilane (Eind)(1-Naph)SiBr2 with lithium naphthalenide. The X-ray crystallography shows a highly coplanar (E)-1,2-di(1-naphthyl)disilene skeleton, favorable for the efficient pi-conjugation involving the Si=Si unit, together with a distinct CH-pi interaction between the pen-H atom of 1-naphthyl groups and the aromatic ring of the perpendicularly oriented Eind groups.
• A Convenient Route to Synthetic Analogues of the Oxidized Form of High-Potential Iron-Sulfur Proteins

  Kazuki Tanifuji; Norihiro Yamada; Tomoyuki Tajima; Takahiro Sasamori; Norihiro Tokitoh; Tsukasa Matsuo; Kohei Tamao; Yasuhiro Ohki; Kazuyuki Tatsumi

  INORGANIC CHEMISTRY 53 8 4000 - 4009 2014年04月 [査読有り]
   

  An amide-bound [Fe4S4](3+). cluster, [Fe4S4{N-(SiMe3)(2)}(4)](-) (1), was found to serve as a convenient precursor for synthetic analogues of the oxidized form of high-potential iron sulfur proteins. Treatment of 1 with 4 equiv of bulky thiols led to replacement of the amide ligands with thiolates, giving rise to a series of [Fe4S4(SR)(4)](-) clusters (R = Dmp (2a), Tbt (2b), Eind (2c), Dxp (2d), Dpp (2e); Dmp = 2,6-di(mesityl)phenyl, Tbt = 2,4,6-tris[bis(trimethylsily)methyl]phenyl, Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl, Dxp = 2,6-di(m-xylyl)phenyl, Dpp = 2,6-diphenylphenyl). These clusters were characterized by the mass spectrum, the EPR spectrum, and X-ray crystallography. The redox potentials of the [Fe4S4](3+/2+) couple, -0.82 V (2a), -0.86 V (2b), -0.84 V (2c), -0.74 V (2d), and -0.63 V (2e) vs Ag/Ag+ in THF, are significantly more negative than that of [Fe4S4(SPh)(4)](-/2-) (-0.21 V).
• Controlled isospecific polymerization of α-olefins by hafnium complex incorporating with a trans -cyclooctanediyl-bridged [OSSO]-type bis(phenolate) ligand

  Norio Nakata; Tomoyuki Toda; Tsukasa Matsuo; Akihiko Ishii

  Macromolecules 46 17 6758 - 6764 2013年09月 [査読有り]
   

  Treatment of trans-cyclooctanediyl-bridged [OSSO]-type ligand 1 with Hf(CH2Ph)4 in toluene afforded the corresponding hafnium(IV) dibenzyl complex 5 as pale yellow crystals. X-ray crystallographic analysis of 5 revealed that the six-coordinated hafnium center incorporated in the [OSSO]-type ligand 1 adopted cis-α configuration, and two benzyl ligands were coordinated to hafnium center by η1-fashion. In the polymerization of 1-hexene, the combination of hafnium complex 5 and B(C 6F5)3, (Ph3C)[B(C6F 5)4], or dMAO (dried methylaluminoxane) as an activator provided poly(1-hexene)s with perfect isotacticity ([mmmm] > 95%) and high molecular weights (Mw = 74 800-421 000 g mol-1). The combination of 5/dMAO catalyst system, in particular, exhibited fairly high activity of 2100 g mmol (5)-1 h-1, which is quite higher than those of previously reported [OSSO]-type hafnium complexes. In addition, the polymerization of 4-methyl-1-pentene (4-MP) catalyzed by the 5/(Ph 3C)[B(C6F5)4] system at room temperature produced completely isotactic poly(4-MP)s with good activity (54-101 g mmol (5)-1 h-1) and relatively narrow PDI (M w/Mn = 1.3). Furthermore, the propylene polymerization catalyzed by the 5/dMAO system at different temperatures (0-70 C) for 1 h afforded highly isotactic polypropylenes, where the catalyst activity and isotacticity depend on the polymerization temperature. Thus, the activity greatly increased from 500 to 17 000 g mmol (5)-1 h-1 when the polymerization temperature was increased. In contrast, isotacticity and melting transition temperature (Tm) were elevated by decreasing polymerization temperature (at 0 C: [mmmm] = 93.7%, Tm = 156.2 C at 70 C: [mmmm] = 86.8%, Tm = 140.9 C). © 2013 American Chemical Society.
• Synthesis, Structure, and 1-Hexene Polymerization Catalytic Ability of Group 5 Metal Complexes Incorporating an [OSSO]-Type Ligand

  Tomoyuki Toda; Norio Nakata; Tsukasa Matsuo; Akihiko Ishii

  ACS CATALYSIS 3 8 1764 - 1767 2013年08月 [査読有り]
   

  Group 5 metal complexes bearing an [OSSO]-type bis(phenolate) ligand have been successfully prepared by the reaction of a bis(phenol) compound 3 or its dilithio salt 6 with VO(OPr)(3), NbCl5, or TaCl5. X-ray crystallographic analyses revealed the monomeric nature of the resulting complexes, [OSSO]VO(OPr) (5), [0550]NbCl3 (7), and [OSSO]TaCl3 (8), where the metal centers adopted cis-alpha configurations of the [OSSO] tetradentate ligand. The tantalum(V) complex 8 with (Bu3Al)-Bu-i/(Ph3C)[B(C6F5)(4)]as an activator catalyzed the polymerization of 1-hexene to provide completely isotactic poly(1-hexene), with a narrow molecular weight distribution ([mmmm] > 95%, M-w, = 9100 g mol(-1), PDI = 1.6); this is the first group 5 metal catalyst for a-olefin polymerization to afford a highly isospecific polymer.
• Reactions of a Niobium Nitride Complex Prepared from Dinitrogen: Synthesis of Imide and Ureate Complexes and Ammonia Formation

  Fumio Akagi; Shoui Suzuki; Yutaka Ishida; Tsubasa Hatanaka; Tsukasa Matsuo; Hiroyuki Kawaguchi

  EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2013 22-23 3930 - 3936 2013年08月 [査読有り]
   

  A nitride complex [K(thf)(2)](2)[{(O-3)Nb}(2)(-N)(2)] (2), prepared from [K(DME)](2)[{(O-3)Nb}(2)(-H)(4)] (1) and N-2, was protonated with 2,6-lutidinium chloride to yield ammonia and [(O-3)NbCl3](-) (3), where H-3[O-3] = tris(3,5-di-tert-butyl-2-hydroxy phenyl)methane. The reaction of 3 with KBHEt3 regenerated [K(DME)](2)[{(O-3)Nb}(2)(-H)(4)] (1), thereby completing a synthetic cycle for the conversion of N-2 to NH3. Alkylation of 2 with methyl iodide led to formation of [K(thf)][{(O-3)Nb}(2)(-N)(-NMe)] (4) and [{(O-3)Nb}(2)(-NMe)(2)] (5). Treatment of 5 with pyridine afforded a terminal imide complex [(O-3)Nb=NMe(py)(2)] (6). The imide monomer 6 reacted with CO2 to give [(O-3)Nb{(MeN)(2)CO}(py)] (7) and [{(O-3)Nb}(2)(-O)(2)] (8) in a 2:1 ratio, while the reaction of 6 with p-TolNCO gave an asymmetric ureate complex [(O-3)Nb{p-TolNC(O)NMe}(py)] (9).
• Intramolecular [2+2+2] cycloaddition of bis(propargylphenyl)carbodiimides: synthesis of L-shaped π-extended compounds with pyrrolo[1,2-a][1,8]naphthyridine corner units.

  Otani T; Saito T; Sakamoto R; Osada H; Hirahara A; Furukawa N; Kutsumura N; Matsuo T; Tamao K

  Chemical communications (Cambridge, England) 49 55 6206 - 6208 55 2013年 [査読有り]
   

  L-shaped pi-extended penta-, hexa-, and heptacycles with a pyrrolo[1,2-a][1,8] naphthyridine junction were prepared from N,N'-bis[2-(2-alkyn-1-yl)phenyl]carbodiimides or their naphthyl analogs via Rh(I)-catalyzed intramolecular [2+2+2] cycloaddition and dehydrogenative aromatization. These L-shaped compounds emit sky-blue, yellow-green, or golden-orange fluorescence, with high quantum yields.
• A new binding motif of sterically demanding thiolates on a gold cluster

  Jun-Ichi Nishigaki; Risako Tsunoyama; Hironori Tsunoyama; Nobuyuki Ichikuni; Seiji Yamazoe; Yuichi Negishi; Mikinao Ito; Tsukasa Matsuo; Kohei Tamao; Tatsuya Tsukuda

  Journal of the American Chemical Society 134 35 14295 - 14297 2012年09月 [査読有り]
   

  A gold cluster, Au 41(S-Eind) 12, was synthesized by ligating the bulky arenethiol 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacene-4-thiol (Eind-SH) to preformed Au clusters. Extended X-ray absorption fine structure, X-ray photoelectron spectroscopy, and the fragmentation pattern in the mass spectrometry analysis indicated that formation of gold-thiolate oligomers at the interface was suppressed, in sharp contrast to conventional thiolate-protected Au clusters. © 2012 American Chemical Society.
• A New Binding Motif of Sterically Demanding Thiolates on a Gold Cluster

  Jun-ichi Nishigaki; Risako Tsunoyama; Hironori Tsunoyama; Nobuyuki Ichikuni; Seiji Yamazoe; Yuichi Negishi; Mikinao Ito; Tsukasa Matsuo; Kohei Tamao; Tatsuya Tsukuda

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 35 14295 - 14297 2012年09月 [査読有り]
   

  A gold cluster, Au-41(S-Eind)(12), was synthesized by ligating the bulky arenethiol 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacene-4-thiol (Eind-SH) to preformed Au clusters. Extended X-ray absorption fine structure, Xray photoelectron spectroscopy, and the fragmentation pattern in the mass spectrometry analysis indicated that formation of gold thiolate oligomers at the interface was suppressed, in sharp contrast to conventional thiolate-protected Au clusters.
• A stable germanone as the first isolated heavy ketone with a terminal oxygen atom

  Liangchun Li; Tomohide Fukawa; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  NATURE CHEMISTRY 4 5 361 - 365 2012年05月 [査読有り]
   

  The carbon-oxygen double bond of ketones (R2C=O) makes them among the most important organic compounds, but their homologues, heavy ketones with an E=O double bond (E = Si, Ge, Sn or Pb), had not been isolated as stable compounds. Their unavailability as monomeric molecules is ascribed to their high tendency for intermolecular oligomerization or polymerization via opening of the E=O double bond. Can such an intermolecular process be inhibited by bulky protecting groups? We now report that it can, with the first isolation of a monomeric germanium ketone analogue (Eind)(2)Ge=O (Eind=1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl), stabilized by appropriately designed bulky Eind groups, with a planar tricoordinate germanium atom. Computational studies and chemical reactions suggest the Ge=O double bond is highly polarized with a contribution of a charge-separated form (Eind)(2)Ge+-O-. The germanone thus exhibits unique reactivities that are not observed with ordinary ketones, including the spontaneous trapping of CO2 gas to provide a cyclic addition product.
• Titanium Complexes Supported by an [OSSO]-Type Bis(phenolato) Ligand Based on a trans-eCyclooctanediyl Platform: Synthesis, Structures, and 1-Hexene Polymerization

  Norio Nakata; Tomoyuki Toda; Tsukasa Matsuo; Akihiko Ishii

  INORGANIC CHEMISTRY 51 1 274 - 281 2012年01月 [査読有り]
   

  trans-Cyclooctanediyl-bridged [OSSO]-type ligand 4 reacts with TiCl4(thf)(2) in toluene to produce the corresponding titanium(IV) dichloro complexes as an inseparable mixture of cis-alpha isomer 6a and cis-beta isomer 6b in a ratio of 2:1, whereas treatment of dilithio salt of 4 with TiCl3(thf)(3) in Et2O afforded chloride-bridged dimeric titanium(III) complex 8, which indicated the antiferromagnetic character in a nonpolar solvent solution. Di(isopropoxy) titanium(IV) complex 10 having a C-2-symmetric cis-alpha configuration was synthesized by the reaction of 4 with Ti((OPr)-Pr-i)(4) in toluene as yellow crystals. Moreover, the reaction of 4 with Ti(NEt2)(4) in toluene resulted in the unexpected formation of [OSSO]-type bis(phenolato)-bridged dinuclear
• The first observation of electroluminescence from di(2-naphthyl)disilene, an Si=Si double bond-containing π-conjugated compound.

  Tamao K; Kobayashi M; Matsuo T; Furukawa S; Tsuji H

  Chemical communications (Cambridge, England) 48 7 1030 - 1032 7 2012年01月 [査読有り]
   

  Air-stable, room-temperature emissive di(2-naphthyl)disilene, protected by the bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups, can emit light in an organic light-emitting diode, thus providing the first experimental demonstration of electroluminescence from the heavy group 14 unsaturated compounds.
• Sterically demanding imidazolinium salts through the activation and cyclization of formamides

  Michael Tsimerman; Debasis Mallik; Tsukasa Matsuo; Takashi Otani; Kohei Tamao; Michael G. Organ

  CHEMICAL COMMUNICATIONS 48 83 10352 - 10354 2012年 [査読有り]
   

  A new protocol was developed for the synthesis of sterically demanding imidazolinium salts. This procedure was adopted for the synthesis of seven NHC salts, including ones that were demonstrated to be inaccessible using the conventional orthoformate ester type cyclization method.
• Room-Temperature Dissociation of 1,2-Dibromodisilenes to Bromosilylenes

  Katsunori Suzuki; Tsukasa Matsuo; Daisuke Hashizume; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 133 49 19710 - 19713 2011年12月 [査読有り]
   

  A room-temperature dynamic equilibrium between dibromodisilenes and bromosilylenes has been demonstrated by taking advantage of the steric protection using the fused-ring bulky 1,1,3,3,5,5,7,7-octa-R-s-hydrindacen-4-yl (Rind) groups. Although the bromosilylenes cannot be directly observed by spectroscopic methods, the thermal homolytic cleavage of the Si=Si double bond has been confirmed by a pseudo-first-order kinetics for the trapping with bis(trimethylsilyl)acetylene and a crossover reaction using two kinds of Rind-substituted dibromodisilenes. The addition of 4-pyrrolidinopyridine (PPy) to the dibromodisilene leads to an equilibrium mixture between the dibromodisilene and a PPy adduct of bromosilylene, the latter being isolated and characterized. The substitution of the bromine atom in the dibromodisilene by the Grignard reagent is significantly accelerated by the addition of PPy.
• Synthesis and Structures of a Series of Bulky "Rind-Br" Based on a Rigid Fused-Ring s-Hydrindacene Skeleton

  Tsukasa Matsuo; Katsunori Suzuki; Tomohide Fukawa; Baolin Li; Mikinao Ito; Yoshiaki Shoji; Takashi Otani; Liangchun Li; Megumi Kobayashi; Makoto Hachiya; Yoshiyuki Tahara; Daisuke Hashizume; Takeo Fukunaga; Aiko Fukazawa; Yongming Li; Hayato Tsuji; Kohei Tamao

  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 84 11 1178 - 1191 2011年11月 [査読有り]
   

  A series of octa-R-substituted bromo-s-hydrindacenes, "Rind-Br," have been synthesized by a sequence of the Lewis acid catalyzed intramolecular Friedel-Crafts reaction, bromination and vice versa. Their structural features and physical properties depend on the eight R-substituents at the four benzylic positions on the s-hydrindacenyl skeleton. The molecular structures of the Rind-Br have been confirmed by X-ray crystallography, indicating the unique structural diversities of the bulky Rind groups.
• Boron-Boron σ-Bond Formation by Two-Electron Reduction of a H-Bridged Dimer of Monoborane.

  Shoji Y; Matsuo T; Hashizume D; Gutmann MJ; Fueno H; Tanaka K; Tamao K

  Journal of the American Chemical Society 133 29 11058 - 11061 2011年07月 [査読有り]
   

  Diborane(6) as a H-bridged dimer of mono-borane can be converted cleanly by two-electron reduction into diborane (6) dianion, which is isoelectronic with ethane, through B-B sigma-bond formation when each boron atom has a bulky ligand on it. The existence of the B B sigma bond is supported by the X-ray molecular structure [B-B bond length of 1.924(3) angstrom], NMR studies, magnetic susceptibility measurements, and DFT calculations. Stepwise hydride abstraction reactions of the diborane(6) dianion produce the corresponding H-bridged diborane (5) anion and doubly H-bridged diborane(4) without B-B bond scission.
• Neutral and Cationic Gold(I) Complexes with pi-Conjugated Phosphasilene Ligands

  Baolin Li; Tsukasa Matsuo; Takeo Fukunaga; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  ORGANOMETALLICS 30 13 3453 - 3456 2011年07月 [査読有り]
   

  A series of neutral and cationic Au(I) complexes incorporating pi-conjugated phosphasilene ligands stabilized by the bulky 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl (Rind) groups have been synthesized. X-ray crystallographic studies show the eta(1)-coordination mode of the phosphasilene ligand, accommodating the linear trans two-coordinate geometry around the gold center. While the metal coordination slightly enhances the intensity of the strong pi-pi* absorption of the phosphasilene chromophores, the phosphashilene pi-conjugation is not extended through the Au atom.
• Air- and Moisture-Stable p-Monothiobenzoquinones Incorporated in an Octaalkyl-s-hydrindacene Skeleton

  Makoto Hachiya; Mikinao Ito; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  ORGANIC LETTERS 13 10 2666 - 2669 2011年05月 [査読有り]
   

  p-Monothiobenzoquinones incorporated in a fused-ring octaalkyl-s-hydrindacene skeleton have been synthesized as air- and moisture-stable reddish orange, crystals by the oxidation of mercaptophenol derivatives with DDQ, which have been characterized by X-ray crystallography to show a planar quinoid framework.
• Synthesis and structures of dialkyl zirconium complexes with an [OSSO]-type bis(phenolate) ligand bearing a trans-1,2-cyclooctanediylbis(thio) unit

  Tomoyuki Toda; Norio Nakata; Tsukasa Matsuo; Akihiko Ishii

  JOURNAL OF ORGANOMETALLIC CHEMISTRY 696 6 1258 - 1261 2011年03月 [査読有り]
   

  Dimethyl and bis[(trimethylsilyl) methyl] zirconium complexes ([OSSO]ZrR2) [4, R = Me; 5, R = CH2SiMe3] having [OSSO]-type bis(phenolato) ligand 1 based on the trans-1,2-cyclooctanediylbis(thio) core have been synthesized by the reactions of the corresponding dichloro zirconium complex 3 with 2 equiv. of MeMgBr and Me3SiCH2MgCl, respectively, in Et2O/toluene at -78 degrees C. The molecular structures of these complexes 3-5 were characterized by NMR spectroscopy, elemental analyses, and X-ray crystallography. H-1 and C-13 NMRdata of complexes 3-5 exhibited that they took the C-2-symmetry in solution in the NMRtime scale. In the crystal structures of 3-5, each zirconium center lies at the center of a distorted octahedral coordination sphere with cis sulfur atoms and trans oxygen atoms, which adopts a cis-alpha [(Lambda*, S*, S*)] configuration. (C) 2010 Elsevier B.V. All rights reserved.
• A Planar Rhombic Charge-Separated Tetrasilacyclobutadiene

  Katsunori Suzuki; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  SCIENCE 331 6022 1306 - 1309 2011年03月 [査読有り]
   

  The cyclobutadiene (CBD) molecule C4H4 deviates from a high-symmetry square geometry to compensate for its antiaromatic electronic structure. Here, we report a CBD silicon analog, Si-4(EMind)(4) (1), stabilized by the bulky 1,1,7,7-tetraethyl-3,3,5,5-tetramethyl-s-hydrindacen-4-yl (EMind) groups, obtained as air-and moisture-sensitive orange crystals by the reduction of (EMind)SiBr3 with three equivalents of lithium naphthalenide. X-ray crystallography reveals a planar and rhombic structure of the Si-4 four-membered ring, with alternating pyramidal and planar configurations at the silicon atoms. The large Si-29 chemical shift differences (Delta delta > 350 parts per million) in the solid-state nuclear magnetic resonance spectra suggest a contribution of an alternately charge-separated structure. The rhombic-shaped charge-separated singlet state of compound 1 thus stabilizes its cyclic 4 pi-electron antiaromaticity in a manner that contrasts sharply with the bond-length alternation, characterizing the rectangular distortion of carbon-based CBD.
• The Synthesis of Highly Coplanar Oligothiophenes Induced by Bulky Rind Groups

  Takashi Otani; Makoto Hachiya; Daisuke Hashizume; Tsukasa Matsuo; Kohei Tamao

  CHEMISTRY-AN ASIAN JOURNAL 6 2 350 - 354 2011年02月 [査読有り]
  
• Synthesis and reactivity of niobium complexes having a tripodal triaryloxide ligand in bidentate, tridentate, and tetradentate coordination modes

  Fumio Akagi; Yutaka Ishida; Tsukasa Matsuo; Hiroyuki Kawaguchi

  DALTON TRANSACTIONS 40 10 2375 - 2382 2011年 [査読有り]
   

  The synthesis and reactivity of niobium complexes incorporating a tripodal triphenol (tris(3,5-tert-butyl-2-hydroxylphenyl)methane = H-3[O-3]) have been investigated. Addition of one equivalent of NbCl5 in CH3CN to H-3[O-3] in toluene led to partial HCl elimination, giving [H(O-3)]NbCl3(CH3CN) (1) with a bidendtate bis(aryloxide) ligand and a pendant phenol arm. Treatment of 1 with THF afforded [H(O-3)]NbCl3(THF) (2). Deprotonation of 1 with NEt3 in toluene promoted coordination of the pendant phenol group to generate (Et3NH)[(syn-O-3)NbCl3] (3-syn). Prolonged heating of 3-syn resulted in clean conversion to the anti isomer (3-anti). Attempted deprotonation of 2 with PhCH2MgCl provided [H(O-3)]Nb(CH2Ph)(3) (4), in which alkylation took place at the metal center but the pendant phenol arm remained intact. When 3-syn was treated with PhCH2MgCl, [O3C]Nb(CH2Ph) (5) was produced via C-H activation of the methine C-H bond. The analogous reaction with 3-anti provided a benzylidene complex [anti-O-3]Nb(CHPh)(THF) (6). During the course of the reaction, the anti ligand conformation is retained. Upon heating, 4 underwent methine C-H and phenol O-H activation, yielding the metalatrane 5. Complexes 1, 3-syn, 3-anti, 4, and 5 were characterized by X-ray diffraction.
• Synthesis and Structures of a Series of Bulky "Rind-Br" Based on a Rigid Fused-Ring s-Hydrindacene Skeleton

  Tsukasa Matsuo; Katsunori Suzuki; Tomohide Fukawa; Baolin Li; Mikinao Ito; Yoshiaki Shoji; Takashi Otani; Liangchun Li; Megumi Kobayashi; Makoto Hachiya; Yoshiyuki Tahara; Daisuke Hashizume; Takeo Fukunaga; Aiko Fukazawa; Yongming Li; Hayato Tsuji; Kohei Tamao

  Bulletin of the Chemical Society of Japan 84 11 1178 - 1191 2011年 [査読有り]
   

  A series of octa-R-substituted bromo-s-hydrindacenes, "Rind-Br," have been synthesized by a sequence of the Lewis acid catalyzed intramolecular FriedelCrafts reaction, bromination and vice versa. Their structural features and physical properties depend on the eight R-substituents at the four benzylic positions on the s-hydrindacenyl skeleton. The molecular structures of the Rind-Br have been confirmed by X-ray crystallography, indicating the unique structural diversities of the bulky Rind groups. © 2011 The Chemical Society of Japan.
• COORDINATION CHEMISTRY AND ORGANIC SYNTHESIS UTILIZING CYCLOALKANE-1,2-DITHIOL

  Akihiko Ishii; Tomoyuki Toda; Norio Nakata; Tsukasa Matsuo

  PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 186 5 1169 - 1174 2011年 [査読有り]
   

  An [OSSO]-type tetradentate ligand was prepared starting from trans-cyclooctane-1,2-dithiol. Hexacoordinated dibenzyl Zr complex was synthesized by the reaction of the ligand with Zr(CH2Ph)(4) and its structure was fully characterized by nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography. The zirconium complex has the C-2 symmetry in solution. The zirconium complex activated with B(C6F5)(3) or (Ph3C)[B(C6F5)(4)] provided a highly active catalytic system for coordinate polymerization of 1-hexene to yield poly(1-hexene)s with high isospecificity.
• Air-stable, room-temperature emissive disilenes with π-extended aromatic groups.

  Kobayashi M; Matsuo T; Fukunaga T; Hashizume D; Fueno H; Tanaka K; Tamao K

  Journal of the American Chemical Society 132 43 15162 - 15163 43 2010年11月 [査読有り]
   

  pi-Conjugated disilenes with 2-naphthyl or 2-fluorenyl groups on the silicon atoms have been synthesized as air-stable emissive red solids using the bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups. The strong a pi-pi* absorptions and distinct emission at room temperature, both in solution and in the solid state, have been observed due to the substantial contribution of the 3p(pi)*(Si-Si)-2p(pi)*(carbon pi-electron system) conjugation.
• pi-conjugated phosphasilenes stabilized by fused-ring bulky "Rind" groups

  Tsukasa Matsuo; Baolin Li; Kohei Tamao

  COMPTES RENDUS CHIMIE 13 8-9 1104 - 1110 2010年08月 [査読有り]
   

  Recent progress in the chemistry of pi-conjugated phosphasilenes stabilized by bulky protecting groups based on a fused-ring octa-R-substituted s-hydrindacene skeleton (Rind groups) is reviewed. The phosphasilenes with a variety of aryl substituents at the silicon atom are covered in detail. The X-ray crystallography analysis showed the highly coplanar pi-framework reinforced by the perpendicularly-fixed Rind groups. Strong pi-pi* absorptions have been observed, demonstrating the extension of pi-conjugation over the skeleton. The DFT calculations indicated that the LUMO involves significant contribution by the 3p pi*(Si-P)-2p pi*(carbon pi-electron system) conjugation. The preparation of the gold(I) complexes of the pi-conjugated phosphasilenes is also included. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
• A Stable Doubly Hydrogen-Bridged Butterfly-Shaped Diborane(4) Compound

  Yoshiaki Shoji; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 24 8258 - + 2010年06月 [査読有り]
   

  In contrast to the common multiple bonding between carbon atoms, multiply bonded boron compounds have still been a synthetic challenge due to the electron deficiency of boron. We now report that a stable doubly hydrogen-bridged diborane(4), EindB(mu-H)(2)BEind, is produced by the two-electron oxidation of a hydrogen-substituted diborane(4) dianion [Li(+)(thf)](2)[Eind(H)BB(H)Eind](2-) where Eind denotes the 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl. The X-ray crystallography reveals a short B-B distance of 1.4879(7) angstrom in comparison with the normal B-B single bond length (1.72 angstrom), the presence of two hydrogen atoms bridged perpendicular to the B-B bond with a butterfly shape having a dihedral angle of the two BHB triangles of 113(1)degrees, and a linear geometry around the B-B bond with a C-B-B bond angle of 178.92(4)degrees. These structural data, experimental electron density analysis, and computational studies confirm the 3-fold bonding (a sigma and two pi-like bonds) between the two boron atoms incorporating the two bridging hydrogen atoms.
• Syntheses and structures of zirconium(IV) complexes supported by 2,6-di-adamantylaryloxide ligands and formation of arene-bridged dizirconium complexes with an inverse sandwich structure

  Takahito Watanabe; Yutaka Ishida; Tsukasa Matsuo; Hiroyuki Kawaguchi

  DALTON TRANSACTIONS 39 2 484 - 491 2010年 [査読有り]
   

  The reaction of 2,6-di-adamantyl-4-R-phenol ((ArOH)-O-R, R = Me, Bu-t) with (BuLi)-Bu-n in THF gave good yields of the lithiated derivatives ((ArO)-O-R)Li(THF)(2). Addition of 2 equiv. of ((ArO)-O-R)Li(THF)(2) to ZrCl4(THF)(2) in THF afforded the base-free dichloride complexes ((ArO)-O-R)ZrCl2 (R = Me 1a, Bu-t 1b). The dibenzyl derivative ((ArO)-O-Me)(2)Zr(CH2Ph)(2) 2 was synthesized by addition of 2 equiv. of PhCH2MgCl to 1a in toluene. Reduction of the dichloride complexes 1a and 1b with KC8 in toluene led to the formation of the toluene-bridged dizirconium complexes [((ArO)-O-R)(2)Zr](2)(mu-eta(6):eta(6)-C7H8) (R= Me 3a, Bu-t 3b). A similar reaction was carried out in benzene to produce the corresponding benzene-bridged analogue [((ArO)-O-R)(2)Zr](2)(mu-eta(6):eta(6)-C6H6) (R= Me 4a, Bu-t 4b). Treatment of 3a with 2 equiv. of 1-azidoadamantane (AdN(3)) in THF resulted in the release of toluene and N-2, generating the monomeric imide complex ((ArO)-O-Me)(2)Zr(NAd)(thf) 5. When the analogous reaction was carried out in toluene, ((ArO)-O-Me)(2)Zr(AdNN = NNAd) 6 was obtained. Structures of ((ArO)-O-R)Li(THF)(2), 1a, 2 and 5 were determined by X-ray crystallography.
• π-Conjugated disilenes stabilized by fused-ring bulky "Rind" groups.

  Matsuo T; Kobayashi M; Tamao K

  Dalton transactions (Cambridge, England : 2003) 39 39 9203 - 9208 39 2010年 [査読有り]
   

  Recent advances in the chemistry of p-conjugated disilenes stabilized by the newly developed bulky groups based on a fused-ring octa-R-substituted s-hydrindacene skeleton (Rind groups) are described. The synthesis and characterization of the disilenes with various aryl substituents on the silicon atoms are covered. The highly co-planar pi-frameworks stabilized by the perpendicularly-fixed Rind groups are demonstrated by the X-ray crystallographic analysis. The extension of the pi-conjugation over the diaryldisilene framework is visualized by the photophysical properties such as the UV-vis absorption spectra and the distinct emission both in solution and in the solid state at an ambient temperature.
• Isolated Monomeric and Dimeric Mixed Diorganocuprates Based on the Size-Controllable Bulky "Rind" Ligands

  Mikinao Ito; Daisuke Hashizume; Takeo Fukunaga; Tsukasa Matsuo; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 50 18024 - + 2009年12月 [査読有り]
   

  Isotable mixed diorganocopper(I) complexes have been synthesized and structurally characterized by introducing a variety of bulky "Rind" groups based on a fused-ring octa-R-substituted s-hydrindacene skeleton. Treatment of RindLi with CuBr produced organobromocuprate dimers [Cu(Rind)/CuBr](2) or monomers Li[Cu(Rind)Br], depending on the steric bulkiness of the Rind ligands. Subsequent substitution of the bromine atoms in these complexes by lithium trimethylsilylacetylide gave dimeric and monomeric aryl(alkynyl)copper(l) complexes A and B, respectively. Complex B is the first isolable mixed diorganocuprate monomer formulated as LiCuRR' and was found to selectively undergo oxidative cross-coupling of two different organic groups on copper.
• Zirconium Complex of an [OSSO]-Type Diphenolate Ligand Bearing trans-1,2-Cyclooctanediylbis(thio) Core: Synthesis, Structure, and Isospecific 1-Hexene Polymerization

  Akihiko Ishii; Tomoyuki Toda; Norio Nakata; Tsukasa Matsuo

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 38 13566 - + 2009年09月 [査読有り]
   

  Six-coordinated dibenzyl Zr complex bearing an [OSSO]-type tetradentate ligand was synthesized, and the structure was fully characterized by NMR spectroscopy and X-ray crystallography. The zirconium complex has C(2) symmetry in solution. Owing to an effect of the cyclooctane ring structure, the combination of the zirconium complex and B(C(6)F(5))(3) or (Ph(3)C)[B(C(6)F(5))(4)] as the activator exhibited high activity toward polymerization of 1-hexene to yield highly isotactic poly(1-hexene).
• pi-Conjugated Phosphasilenes Stabilized by Fused-Ring Bulky Groups

  Baolin Li; Tsukasa Matsuo; Daisuke Hashizume; Hiroyuki Fueno; Kazuyoshi Tanaka; Kohei Tamao

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 37 13222 - 13223 2009年09月 [査読有り]
   

  pi-Conjugated phosphasilenes with a variety of aryl substituents on the silicon atom have been synthesized by the use of a 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) group. X-ray structural analysis shows the highly coplanar pi-framework stabilized by the perpendicularly fixed Eind groups. The strong pi-pi* absorptions have been observed, demonstrating the extension of pi-conjugation over the skeleton. The DFT calculations indicate that the LUMO involves the substantial contribution of the 3p pi*(Si- P)-2p(pi)*(carbon pi-electron system) conjugation. The electrochemical properties of the phosphasilens are also presented.
• DFT Study on N-2 Activation by a Hydride-Bridged Diniobium Complex. N N Bond Cleavage Accompanied by H-2 Evolution

  Hiromasa Tanaka; Yoshihito Shiota; Tsukasa Matsuo; Hiroyuki Kawaguchi; Kazunari Yoshizawa

  INORGANIC CHEMISTRY 48 8 3875 - 3881 2009年04月 [査読有り]
   

  Density functional theory (DFT) calculations have been performed for the investigation of a plausible mechanism of the triple bond cleavage of N-2 in a diniobium complex supported by tridentate aryloxide ligands, {Nb-V(mu-N)(2)Nb-V}(2-22) With the assumption of a tetrakis(mu-hydrido)diniobium complex {Nb-IV(mu-H)(4)Nb-IV}(2-) as an initial complex, the N N cleavage on the Nb-2 core proceeds in four steps. Dinitrogen is coordinated to the {Nb-III(mu-H)(2)Nb-III} core in a side-on/end-on manner, accompanied by the reductive elimination of H-2. The N N bond of dinitrogen is activated up to a single bond (formally N-2(4-)) by the two Nb(III) atoms, once it is bound to the Nb-2 core. Two electrons are prepared for the cleavage of the N-N single bond through the mu-H migration to an N atom, leading to the formation of an Nb-Nb bond. The N-N bond is then dissociated by the two electrons that are shared between the two Nb atoms. Finally, {Nb(mu-N)(2)Nb}(2-) is generated after H-2 elimination in which the N-bonded H atom is coupled with the remaining mu-H atom. The final H-2 elimination is calculated to be the rate-determining step.
• Reductive Coupling of Six Carbon Monoxides by a Ditantalum Hydride Complex

  Takahito Watanabe; Yutaka Ishida; Tsukasa Matsuo; Hiroyuki Kawaguchi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 10 3474 - + 2009年03月 [査読有り]
   

  A ditantalum hydride complex undergoes head-to-head C-C coupling of six CO molecules under mild conditions to produce an octaanionic C6O6 unit. During the reaction, eight-electron reduction of six CO molecules takes place. In the product, the C6O6 unit is coordinated to four tantalum metals through six oxygen and two carbon atoms. The geometrical parameters within the Ta4C6O6 core indicate significant contribution from a hexatriene-hexaolate form.
• 玉尾酸化 −炭素とケイ素の織り成す化学−

  松尾 司

  化学と教育 57 9 406 - 407 公益社団法人 日本化学会 2009年 [査読有り]
   

  有機ケイ素化合物とは,炭素-ケイ素結合を有する化合物の総称である。「玉尾酸化」は,炭素-ケイ素結合が過酸化水素により酸化的に切断されてアルコールに変換される反応である。シリル基をヒドロキシル基へと立体特異的に変換する唯一の方法として,重要な有機合成反応の一つとなっている。有機ケイ素化合物の合成化学的有用性を飛躍的に高めた「玉尾酸化」について,その発見物語を中心に紹介する。
• Anisole-diphenoxide Ligands and their zirconium dichloride and dialkyl complexes

  Tsukasa Matsuo; Hiroyuki Kawaguchi

  INORGANIC CHEMISTRY 46 20 8426 - 8434 2007年10月 [査読有り]
   

  Linear triphenol H-3[O-R(3)] (2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-R-phenol; R = Me, Bu-t) was found to undergo selective mono-deprotonation and mono-O-methylation. Deprotonation of H-3[O-R(3)] with 1 equiv of (BuLi)-Bu-n resulted in the formation of Li{H-2[O-R(3)]}(Et2O)(2) (R = Me (1a), Bu-t (1b)), in which the central phenol unit was lithiated. Treatment of H-3[O-R(3)] with methyl p-toluenesulfonate in the presence of K2CO3 in CH3CN gave the corresponding anisol-diphenol H-2[(O2O)-O-R] (2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-R-anisole; R = Me (2a), Bu-t (2b)). Reaction of H-2[(O2O)-O-R] with 2 equiv of (BuLi)-Bu-n gave the dilithiated derivatives Li-2[(O2O)-O-R]. The lithium salts were reacted with ZrCl4 in toluene/THF to obtain the dichloride complex [(O2O)-O-R]ZrCl2(thf) (R = Me (3a), Bu-t (3b)). 3b underwent dimerization along with a loss of THF to generate {[(O2O)-O-tBu]ZrCl2}(2) (4), whereas 4 was dissolved in THF to regenerate the monomer 3b. Alkylation of 3 with MeMgBr, PhCH2MgCl, and Me3SiCH2MgCl gave [(O2O)-O-Me]-ZrMe2(thf) (5), [(O2O)-O-R]Zr(CH2Ph)(2) (R = Me (6a), Bu-t (6b)), and [(O2O)-O-tBu]Zr(CH2SiMe3)(2) (7), respectively. Reaction of 3b with LiBHEt3 produced the hydride-bridged dimer [Li-2(thf)(4)Cl]{[O-tBu(3)]Zr}(2)(mu-H)(3)} (8), in which demethylation of the dianionic [(O2O)-O-tBu] ligand took place to give the trianionic [O-tBu(3)] ligand. The X-ray crystal structures of 1b, 2a, 3a, 4, 6a, and 7 were reported.
• Dinitrogen cleavage by a diniobium tetrahydride complex: Formation of a nitride and its conversion into imide species

  Fumio Akagi; Tsukasa Matsuo; Hiroyuki Kawaguchi

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 46 46 8778 - 8781 2007年 [査読有り]
  
• Zirconium complexes of the tridentate bis(aryloxide)-N-heterocyclic-carbene ligand: Chloride and alkyl functionalized derivatives

  Dao Zhang; Hidenori Aihara; Takahito Watanabe; Tsukasa Matsuo; Hiroyuki Kawaguchi

  JOURNAL OF ORGANOMETALLIC CHEMISTRY 692 1-3 234 - 242 2007年01月 [査読有り]
   

  The disodium salt of a bis(aryloxide)-N-heterocyclic-carbene dianionic ligand, Na-2[L], was prepared by reaction of 1,3-bis(4,6-di-tert-butyl-2-hydroxybenzyl)imidazolium bromide [H3L]Br with 3 equiv. of NaN(SiMe3)(2). Reaction of ZrCl4(thf)(2) with I equiv. of Na-2[L] gave a mixture of [L]ZrCl2(thf) (1) and [L](2)Zr (2). When the amount of Na-2[L] was increased to 2 equiv., the bis(bis(aryloxide)-N-heterocyclic-carbene) complex 2 was obtained in good yield. The dichloro complex I is a precursor to organometallic derivatives, and treatment with PhCH2MgCl or Me3SiCH2Li yielded [L]ZrR2 [R = CH2Ph (3), CH2SiMe3 (4)]. The disodium salt of the ligand Na2[L] is unstable and undergoes 1,2-benzyl migration, whereas zirconium complexes of the [L](2-) ligand are found to be thermally stable in solid and solution. The X-ray crystal structures of 1, 2, and 3 are described. (c) 2006 Elsevier B.V. All rights reserved.
• Doubly charged four-membered ring systems: Cyclobutadiene dianions and heavy cyclobutadiene dianions

  Akira Sekiguchi; Tsukasa Matsuo

  SYNLETT 17 2683 - 2698 2006年10月 [査読有り]
   

  Recent progress in the experimental chemistry of cyclobutadiene dianions (CBD(2-)s) containing a doubly charged four-membered ring system is reviewed. New families of silyl-substituted CBD(2-)s, cyclobutadienes (CBDs), and tetrahedranes are covered in detail. The aromaticity of the tetrasilyl- and diphenyldisilyl-CBD(2-)s have been studied on the basis of structural characteristics and magnetic properties. All of the CBD(2-)s show a strong diatropic ring current resulting from six pi-electron system. The preparation of CBD2- derivatives consisting of heavier group 14 elements (Si and Ge) is also included. They demonstrate a non-aromatic nature with a folded four-membered ring. 1 Introduction 2 Cyclobutadiene Dianions (CBD(2-)s) 2.1 Preparation of CBD Complexes 2.2 Transmetalation of CBD Complexes 2.3 Tetrasilyl-CBD2-S 2.4 Diphenyl-Disityl-CBD2-S 3 Cyclobutadienes (CBDs) 4 Tetrahedranes 5 Heavy Cyclobutadiene Dianions (CBD2-S) 6 Conclusion.
• From carbon dioxide to methane: Homogeneous reduction of carbon dioxide with hydrosilanes catalyzed by zirconium-borane complexes

  Tsukasa Matsuo; Hiroyuki Kawaguchi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128 38 12362 - 12363 2006年09月 [査読有り]
  
• A tantalum(V) carbene complex: Formation of a carbene-bis(phenoxide) ligand by sequential proton and hydride abstraction

  Takahito Watanabe; Tsukasa Matsuo; Hiroyuki Kawaguchi

  INORGANIC CHEMISTRY 45 17 6580 - 6582 2006年08月 [査読有り]
   

  Proton and subsequent hydride abstraction from the bis(phenoxide) ligand of the trimethyltantalum(V) complex affords a cationic tantalum(V) carbene complex, in which two phenoxide groups are linked to the carbene center. The electrophilic nature of the carbene functionality is demonstrated by the reaction with PPh3.
• A synthetic cycle for H-2/CO activation and allene synthesis using recyclable zirconium complexes

  T Matsuo; H Kawaguchi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127 49 17198 - 17199 2005年12月 [査読有り]
  
• Complexes of tantalum with triaryloxides: Ligand and solvent effects on formation of hydride derivatives

  H Kawaguchi; T Matsuo

  JOURNAL OF ORGANOMETALLIC CHEMISTRY 690 23 5333 - 5345 2005年11月 [査読有り]
   

  A family of tantalum compounds supported by the triaryloxide [R-L](3-) ligands are reported [H-3(R-L) = 2,6-bis(4-methyl-6-R-salicyl)-4-tert-butylphenol, where R = Me or 'Bu]. The reaction of H-3[Me-L] with TaCl5 in toluene gave [(Me-L)TaCl2](2) (1). The ['Bu-L] analogue [('Bu-L)TaCl2](2) (2) was synthesized via treatment of TaCl5 with Li-3['Bu-L]. A THF solution of LiBHEt3 was added to 1 in toluene to provide [(Me-L)TaCl(THF)](2) (3), while treatment of 2 with 2 equiv of LiBHEt3 or potassium in toluene followed by recrystallization from DME resulted in formation of [M(DME)(3)][{('Bu-L)TaCl)(2)(mu-Cl)] [M = Li (4a), K (4b)]. When the amount of MBHEt3 (M = Li, Na, K) was increased to 5 equiv, the analogous reactions in toluene afforded [ (bit-'Bu-L)Ta}(2) (mu-H)(3)M] [M = Li(THF)(2) (5a), Na(DME)(2) (5b), K(DME)(2) (5c)]. During the course of the reaction, the methylene CH activation of the ligand took place. Dissolution of 5a in DME produced [{(bit-'Bu-L)Ta}(2)(mu-H)(3)Li(DME)(2)] (6), indicating that the coordinated THF molecules are labile. When the 2/LiBHEt3 reaction was carried out in THF, the ring opening of THF occurred to yield [('Bu-L)Ta(OBu '')(2)](2) (7) along with a trace arnount of [Li(THF)(4)][{('Bu-L)TaCl}(2)(mu-OBu '')] (8). Treatment of 2 with potassium hydride in DME yielded [ ('Bu-L)TaCl2K(DME)(2)}(2)(mu-OCH2CH2O)] (9), in which the ethane-1,2-diolate ligand arose from partial C-O bond rupture of DME. The X-ray crystal structures of 2, 3, 4, 5a, 6, 7, and 9 are described. (c) 2005 Published by Elsevier B.V.
• Titanium and zirconium complexes of preorganized tripodal triaryloxide ligands

  F Akagi; T Matsuo; H Kawaguchi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127 34 11936 - 11937 2005年08月 [査読有り]
  
• Synthesis of a vanadium(III) tris(arylthiolato) complex and its reactions with azide and azo compounds: Formation of a sulfenamide complex via cleavage of an azo N=N bond

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  INORGANIC CHEMISTRY 44 2 175 - 177 2005年01月 [査読有り]
   

  The tris(arylthiolate) vanadium(III) complex (1) has been synthesized in good yield. This complex is found to undergo CH activation across a V-S bond in the presence of TMEDA to give a cyclometalated species along with free arylthiol. Complex 1 behaves as a two-electron reductant toward Ad-N-3 yielding an imide complex. Treatment of 1 with azobenzene produces an imide-sulfenamide compound, in which an azo N=N bond cleavage takes place concomitant with formation of a V=N and an S-N bond.
• Aryloxide-​based multidentate ligands for early transition metals and f-​element metals

  Kawaguchi, Hiroyuki; Matsuo, Tsukasa

  Journal of Organometallic Chemistry 689 24 4228 - 4243 2004年11月 [査読有り]
   

  This article presents an overview of the chemistry of early transition metal and f-element complexes stabilized by aryloxide-based multidentate ligands. Preparations and reactivity studies of these compounds are discussed. The presence of the bridging units in this ligand system imposes a strong geometry constraint to the aryloxide groups, which leads the way to novel patterns of structure and reactivity. (C) 2004 Elsevier B.V. All rights reserved.
• Tridentate aryloxide ligands: New supporting Ligands in coordination chemistry of early transition metals

  T Matsuo; H Kawaguchi

  CHEMISTRY LETTERS 33 6 640 - 645 2004年06月 [査読有り]
   

  The use of covalently linked multidentate ligands is a very useful concept in coordination and organometallic chemistry. This article gives an account of the syntheses and structures of metal complexes supported by linear-linked aryloxide trimer ligands, in which aryloxide units are connected at ortho positions through methylene linkers.
• Tetrasilyl-substituted cyclobutadiene dianion dilithium salt: synthesis and structure

  A Sekiguchi; T Matsuo; M Tanaka; H Watanabe; M Nakamoto

  RUSSIAN CHEMICAL BULLETIN 53 5 1109 - 1115 2004年05月 [査読有り]
   

  The reaction of tetrakis(trimethylsilyl)cyclobutadienylcyclopentadienyl cobalt complex (Me3Si)(4)C4CoCp with lithium metal in THF yielded the dilithium salt of cyclobutadiene dianion CBD2- stabilized by four trimethylsilyl groups, Li-2(+)[(Me3Si)(4)C-4](2-). The bridged CBD2- dianion was also synthesized by a similar procedure starting from the bridged cobalt complex, which was prepared from the reaction of 2,2,5,5,8,8,11,11-octamethyl-2,5,8,11-tetrasilacyclododeca-1,6-diyne with CpCo(CO)(2) in refluxing octane. The aromaticity of the CBD2- is discussed on the basis of the structural characteristics and magnetic properties.
• Cyclobutadiene dianion

  T Matsuo; A Sekiguchi

  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 77 2 211 - 226 2004年02月 [査読有り]
   

  In this account, we present the synthesis and chemistry of the dilithium salts of the cyclobutadiene dianion (CBD2-), which contains a doubly charged four-membered ring system. The transmetalation reaction of tetrasilyl-substituted cyclo-butadiene (CBD) cobalt complexes (5,6) with lithium metal led to the formation of the corresponding dilithium salts of CBD2- (10,11). The aromaticity of the CBD2- Species has been studied on the basis of structural characteristics and magnetic properties. The dilithium salts of CBD2- stabilized by both phenyl and silyl groups (12-14) were also prepared by a similar procedure, starting from the corresponding CBD cobalt complexes (7-9). The CBD2- species have been fully characterized by NMR studies and X-ray crystallography. The two-electron oxidation reaction of the tetrasilyl-CBD2- (10,11) with 1,2-dibromoethane produced the neutral CBD derivatives (17,22). The structures, properties, and reactivities of the tetrasilyl-substituted CBD are also reviewed here. Tetrakis(trimethylsilyl)tetrahedrane (26) was synthesized by irradiation of tetrakis(trimethylsilyl)cyclobutadiene (17). The Structure and properties of tetrahedrane (26) are presented.
• Synthesis and structural characterization of silanethiolato complexes having tert-butyldimethylsilyl and trimethylsilyl groups

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  DALTON TRANSACTIONS 10 1618 - 1625 2004年 [査読有り]
   

  Treatment of cyclotrisilathiane (Me2SiS)(3) with 3 equiv. of RLi (R = Me, Bu-t) in hexane-Et2O afforded the lithium silanethiolates LiSSiMe2R, and the tmeda adduct [(tmeda) LiSSiMe2But](2) 1 (tmeda = N, N, N', N'-tetramethylethylenediamine) was isolated in the case of R = Bu-t. Reaction of Fe(CH3CN)(2)(CF3SO3)(2), CoCl2, and [Cu(CH3CN)(4)](PF6) with 1 gave rise to the silanethiolato complexes M(SSiMe2But)(2)( tmeda) (M = Fe 2, Co 3), and [Cu(SSiMe2But)](4) 4, respectively. Complexes (C5H5)(2)Ti(SSiMe2R)(2) (R = Me 5, Bu-t 6) and Ni(SSiMe2R)(2)(dppe) [R = Me 7, Bu-t 8; dppe = 1,2-bis(diphenylphosphino) ethane] were prepared from treatments of (C5H5)(2)TiCl2 and NiCl2(dppe) with the corresponding lithium silanethiolates. Complex 7 readily reacted with (C5H5) TiCl3 to produce the Ti - Ni heterobimetallic compound (C5H5) TiCl(mu-S)(2)Ni(dppe) 9, in which silicon - sulfur bond cleavage took place. Characterization of all compounds through spectroscopic techniques and elemental analyses are also described. X-Ray structural data for compounds 1 and 3 - 9 are reported.
• Formation of an iron(II) carbene-thiolato complex by insertion of carbon monoxide into an Si-C bond

  M Yuki; T Matsuo; H Kawaguchi

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43 11 1404 - 1407 2004年 [査読有り]
  
• Triple-​Hydrogen-​Bridged Dititanium(III) and Dizirconium(IV) Aryloxide Complexes

  Matsuo, Tsukasa; Kawaguchi, Hiroyuki

  Organometallics 22 26 5379 - 5381 2003年12月 [査読有り]
   

  The triple-hydrogen-bridged dititanium(III) complex was prepared by the reaction of the titanium(IV) aryloxide complex with LiBHEt3, while a similar reaction using the zirconium aryloxide complex gave the triple-hydrogen-bridged dizirconium(IV) complex. The titanium(III) dimer was found to be diamagnetic, and its dynamic behavior in solution was revealed by NMR studies.
• Aryl-oxygen bond cleavage by a trihydride-bridging ditantalum complex

  H Kawaguchi; T Matsuo

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 47 14254 - 14255 2003年11月 [査読有り]
  
• Coordination chemistry of silanedithiolato ligands derived from cyclotrisilathiane: Synthesis and structures of complexes of iron(II), cobalt(II), palladium(II), copper(I), and silver(I)

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  INORGANIC CHEMISTRY 42 17 5340 - 5347 2003年08月 [査読有り]
   

  The coordination chemistry of chelating silanedithiolato ligands has been investigated on Fe(II), Co(II), Pd(II), Cu(I), and Ag(I). Treatment of M(OAc)(2) (M = Fe, Co, Pd) with cyclotrisiiathiane (SSiMe2)(3) in the presence of Lewis bases resulted in formation of Fe(S2SiMe2)(PMDETA) (1), Fe(S2SiMe2)(Me(3)TACN) (2), Co(S2SiMe2)(PMDETA) (3), and Pd(S2SiMe2)(PEt3)(2) (4) (PMDETA = N,N,N',N',N' -pentamethyldiethylenetriamine; Me(3)TACN = 1,4,7-trimethyl- 1,4,7-triazacyclononane). The analogous reactions of M(OAc) (M = Cu, Ag) in the presence of PEt3 gave rise to the dinuclear complexes M-2{(SSiMe2)(2)S}(PEt3)(3) [M = Cu (5), Ag (6)]. Complexes were characterized in solution by H-1, P-31{H-1}, and Si-29{H-1} NMR and in the solid state by single-crystal X-ray diffraction. Mononuclear complexes 1-3 have a four-membered MS2Si ring, and these five-coordinate complexes adopt trigonal-bipyramidal (for the PMDETA adducts) or square-pyramidal (for the Me(3)TACN adduct) geometries. In dimer 6, the (SSiMe2)(2)S(2-)silanedithiolato ligand bridges two metal centers, one of which is three-coordinate and the other four-coordinate. The chelating effect of silanedithiolato ligands leads to an increase in the stability of silylated thiolato complexes.
• Unusual coordination modes of arylthiolates in Mo{eta(5)-SC6H3-2,6-(SiMe3)(2)} {eta(7)-SC6H3-2,6-(SiMe3)(2)}

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125 8 2070 - 2071 2003年02月 [査読有り]
  
• Copper and silver complexes containing the S(SiMe2S)(2)(2-) ligand: Efficient entries into heterometallic sulfido clusters

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42 4 465 - + 2003年 [査読有り]
  
• Titanium N-heterocyclic carbene complexes incorporating an imidazolium-linked bis(phenol)

  H Aihara; T Matsuo; H Kawaguchi

  CHEMICAL COMMUNICATIONS 17 2204 - 2205 2003年 [査読有り]
   

  The synthesis and characterization of titanium complexes of the aryloxido-functionalized N-heterocyclic carbene ligand (L) is reported, in which the tridentate L ligand meridionally coordinates to the metal center.
• Synthesis and structures of nioblum(V) complexes stabilized by linear-linked aryloxide trimers

  T Matsuo; H Kawaguchi

  INORGANIC CHEMISTRY 41 23 6090 - 6098 2002年11月 [査読有り]
   

  The preparation and characterization of a series of niobium(V) complexes that incorporate the linear-linked aryloxide trimers 2,6-bis (4,6-dimethylsalicyl)-4-tert-butyl phenol [H-3(Me-L)] and 2,6-bis(4-methyl-6-tert-butylsalicyl)-4-tertbutylphenol [H-3(Bu-t-L)] are described. The chloride complex [Nb(Me-L)Cl-2](2) (1) was prepared in high yield by reaction of NbCl5 with H-3(Me-L) in toluene. In contrast, the analogous reaction with H-3(Bu-t-L) gave a mixture of [Nb(Bu-t-L)Cl-2](2) (2) and [Nb(de-Bu-t-L)Cl-2](2) (3a). During the formation of 3a, one of tert-butyl groups at the ortho position in the tBu-L ligand was lost. When the NbCl5(H-3(Bu-t-L) reaction was carried out in acetonitrile, Nb[H(Bu-t-L)]Cl-3(NCMe) (4) was obtained. Heating a solution of 4 in toluene generated 2 and 3a. The isolated complex 4 underwent ligand redistribution in acetonitrile to produce Nb[H(Bu-t-L)](2)Cl(NCMe) (5). Treatment of NbCl5 with Li-3(Bu-t-L) in toluene afforded 2. The chloride ligands in 1 and 2 smoothly reacted with 4 equiv of MeMgl and (LiSBu)-Bu-t, resulting in [Nb(R-L)Me-2](2) [R = Me (6), Bu-t (7)] and Nb(Me-L)((SBu)-Bu-t)(2) (8), respectively. A number of the above complexes have been characterized by X-ray crystallography. In the structures of 1, 2, and 6, the R-L ligand is bound to the metal center with a U-coordination mode, while an alternative S-conformation is adopted for 3a and 8. Complexes 4 and 5 contain a bidentate H(Bu-t-L) diphenoxide-monophenol ligand.
• Tetrakis(trimethylsilyl)tetrahedrane

  G Maier; J Neudert; O Wolf; D Pappusch; A Sekiguchi; M Tanaka; T Matsuo

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 124 46 13819 - 13826 2002年11月 [査読有り]
   

  Tetrakis(trimethylsilyl)tetrahedrane 3 has been synthesized upon irradiation of tetrakis(trimethylsilyl)cyclobutadiene 8, which can be prepared either by thermal nitrogen elimination from trimethylsilyl-[1,2,3-tris(trimethylsilyl)-2-cycloprop-1-enyl]diazomethane 7 or by mild oxidation of cyclobutadiene dianion 9 with 1,2-dibromoethane. The structural characterization of tetrahedrane 3 has been achieved by X-ray crystallography. The surprising thermal stability of 3 - which is stable up to 300 degreesC - is discussed.
• Aromaticity of the cyclobutadiene dianion: Structural characteristics and magnetic properties

  A Sekiguchi; T Matsuo; M Tanaka

  ORGANOMETALLICS 21 6 1072 - 1076 2002年03月 [査読有り]
   

  The dilithium salts of cyclobutadiene dianions (CBD2-), 1,2-diphenyl-3,4-bis(trimethylsilyl)cyclobutadiene dianion dilithium (3), and 1,3-diphenyl-2,4-bis(trimethylsilyl)cyclobutadiene dianion dilithium (4) have been synthesized by the reaction of the corresponding cyclobutadiene cobalt complexes with lithium metal in tetrahydrofuran (THF). The dilithium salts were isolated as air- and moisture-sensitive crystals, and their molecular structures, containing two molecules of 1,2-dimethoxyethane (DME), were determined by X-ray crystallography. Each of the CBD2- has a monomeric structure and forms contact ion pairs (CIPs) in the crystal. The two Li+ ions are located above and below the plane of the four-membered ring and are bonded to the four quaternary carbon atoms. The cyclobutadienediide ring of the cis-diphenyl CBD2- (3) shows a conspicuous trapezoid structure, whereas that of the trans-diphenyl CBD2- (4) shows a slightly rhomboid structure, The Li-7 NMR spectra of the CBD2- indicate that the two lithium atoms are considerably shielded by a diatropic ring current, resulting from the six-pi-electron system.
• Binuclear iron(II) complex from a linked-bis(amidinate) ligand: synthesis and its reaction with carbon monoxide

  H Kawaguchi; T Matsuo

  CHEMICAL COMMUNICATIONS 9 958 - 959 2002年 [査読有り]
   

  Binuclear iron(II) complexes supported by a cyclohexane-linked bis(amidinate) ligand have been isolated and structurally characterized.
• Palladium dimethylsilanedithiolato complex: a precursor for Ti-Pd and Ti-Pd-2 heterometallic complexes

  T Komuro; T Matsuo; H Kawaguchi; K Tatsumi

  CHEMICAL COMMUNICATIONS 9 988 - 989 2002年 [査読有り]
   

  The silanedithiolato complex Pd(S2SiMe2)(PEt3)(2) 1 reacted with (C5H5)TiCl3 and TiCl4(thf)(2) to produce the heterometallic clusters (C5H5)TiCl(mu-S)(2)Pd(PEt3)(2) 2 and TiCl2(S)(mu-S)(2)Pd-2(PEt3)(4) 3 along with silicon-sulfur bond cleavage, respectively.
• Dinitrogen-bond cleavage in a niobium complex supported by a tridentate aryloxide ligand

  H Kawaguchi; T Matsuo

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 41 15 2792 - + 2002年 [査読有り]
  
• Reduction of tetrakis(trimethylsilyl)​butatriene by lithium: Monomeric and dimeric structures of the dilithium butatriene dianion

  Sekiguchi, Akira; Tanaka, Masanobu; Matsuo, Tsukasa

  Silicon Chemistry 1 5/6 345 - 350 2002年 [査読有り]
  
• Synthesis and structures of Ti(III) and Ti(IV) complexes supported by a tridentate aryloxide ligand

  T Matsuo; H Kawaguchi; M Sakai

  JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS 12 2536 - 2540 2002年 [査読有り]
   

  Titanium complexes of the tridentate aryloxide Me-L3- [H-3 (Me-L) = 2,6-bis(4,6-dimethylsalicyl)-4-tert-butylphenol] have been prepared. Reaction of TiCl4 with 1 equivalent of H-3 (Me-L) gave [Ti( Me-L) Cl](2) 1. Recrystallization of 1 from THF resulted in formation of the THF adduct Ti(Me-L) Cl(THF)(2) 2. Treatment of 1 with [NEt4]Cl in THF quantitatively gave [NEt4][Ti-2 (Me-L)(2) Cl-3] 3. Complex 1 was reduced with 2 equivalents of potassium to produce the Ti(III) complex [Ti( Me-L)(DME)](2) 4. Structures of 1, 2, 3 and 4 have been determined by X-ray analyses. For 1, 2 and 4, the Me-L ligand assumes a U-conformation. In the case of 3, it is coordinated in an S-conformation.
• Observation of the predicted Negative faraday a MCD term in a cyclobutadiene dianion

  K Ishii; N Kobayashi; T Matsuo; M Tanaka; A Sekiguchi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 123 22 5356 - 5357 2001年06月 [査読有り]
  
• From a cyclobutadiene dianion to a cyclobutadiene: Synthesis and structural characterization of tetrasilyl-substituted cyclobutadiene

  A Sekiguchi; M Tanaka; T Matsuo; H Watanabe

  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 40 9 1675 - 1677 2001年 [査読有り]
  
• Isolation and characterization of the monomeric and dimeric structures of tetrakis(trimethylsilyl)​butatriene dianion dilithium

  Tsukasa; Tanaka, Masanobu; Sekiguchi, Akira

  Chemical Communications 5 503 - 504 2001年 [査読有り]
   

  Tetrakis(trimethylsilyl)butatriene reacted with lithium metal in tetrahydrofuran to yield yellow crystals of the monomeric and dimeric molecules of the butatriene dianion dilithium with a lithium doubly bridged bisallylic structure.
• Cyclobutadiene dianion dilithium: a new aromatic ring system

  A Sekiguchi; T Matsuo; H Watanabe

  PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS 168 51 - 58 2001年 [査読有り]
   

  The reaction of tetrakis(trimethylsilyl)- (or cis-diphenyl) cyclobutadiene cobalt complexes with lithium metal in THF at room temperature produced the dilithium salts of tetrakis(trimethylsilyl)- (or cis-diphenyl) cyclobutadiene dianion, which were isolated as pale yellow (or pale orange) solids stable in the absence of air. NMR spectra and X-ray crystallography of these dianions provide the evidence for an aromatic character with a six pi -electron system.
• Synthesis and Reduction of Silyl-​Substituted [5]​Radialene. Characterization and Structure of a [5]​Radialene Tetraanion with a Ten-​Center, Fourteen-​Electron π-​System

  Matsuo, Tsukasa; Fure, Hidetoshi; Sekiguchi, Akira

  Bulletin of the Chemical Society of Japan 73 9 2129 - 2137 2000年09月 [査読有り]
   

  The reaction of 3,3,6,6,8,8,11,11,14,14,16,16,19,19,21,21-hexadecamethyl-3,6,8,11,14,16,19,21-octasilacyclohenicosa-1,4,9,12,17-pentayne with an excess molar amount of [Mn(CO)(3)(Me-Cp)] in tetrahydrofuran (THF) under photochemical and refluxing conditions produced 2,2,4,4,9,9,11,11,13,13,15,15,17,17,21,21-hexadecamehyl-2,4,9,11,13,15,17,21-octasilahexacyclo[10.5.3.1(5.8).0(6,18),0(7,20)0(14,19)]henicosa-1(18),5,7,12,(20),14(19)-pentaene (2) as silyl-substituted [5]radialene derivative. This was reacted with lithium metal in THF to give dark red crystals of the tetralithium salt (4) of 2. The molecular structure of tetraanion of 2 with a novel ten-center, fourteen-electron pi-system was established by Xray crystallography. The tetralithium salt 4 has a monomeric structure and forms contact ion pairs (tetrakis-CIPs) in the crystals. The structural parameters of 4 are discussed in comparison with those of the neutral starting molecule 2. The structure of 4 in solution is also discussed on the basis of NMR spectroscopic data.
• Synthesis and molecular structure of a dilithium salt of the cis-diphenylcyclobutadiene dianion

  T Matsuo; T Mizue; A Sekiguchi

  CHEMISTRY LETTERS 8 896 - 897 2000年08月 [査読有り]
   

  The cis-diphenyl-substituted cyclobutadiene cobalt complex (1), prepared from the reaction of 1,8-diphenyl-3,6-disila-1,7-octadiyne with CpCo(CO)(2), reacted with lithium metal in tetrahydrofuran (THF) to yield pale orange crystals of the dilithium salt of the cis-diphenylcyclobutadiene dianion (2). The structure was determined by spectroscopic methods and Xray crystallography to reveal the aromatic character of the doubly-charged four-membered ring system.
• A Novel Tetralithium Salt of a Tetraanion and a Dilithium Salt of a Dianion, Formed by the Reduction of the Tetrasilylethylene Moiety. Synthesis, Characterization, and Observation of an Si–H···Li+ Interaction

  Matsuo, Tsukasa; Watanabe, Hidetoshi; Sekiguchi, Akira

  Bulletin of the Chemical Society of Japan 73 7 1461 - 1467 2000年07月 [査読有り]
   

  2,3,6,7-Tetrakis(trimethylsilyl)-1,1,4,4,5,5,8,8-octamethyl-1,4,5,8-tetrasila-1,4,5,8-tetrahydroanthracene (3) was prepared starting from 2,3,6,7-tetrakis(dimethylsilyl)-1,1,4,4,5,5,8,8-octamethyl-1,4,5,8-tetrasila-1,4,5,8-tetrahydroanthracene (1). The molecular structures of 1 and 3 have been determined by X-ray crystallography. Compound 1 has an almost planar structure, whereas compound 3 exhibits a highly folded structure due to the steric repulsion of the trimethylsilyl groups. Treatment of 1 and 3 with lithium metal yielded the corresponding tetralithium salts of the tetraanions 4 and 5, in which the two tetrasilylethylene units were subjected to two-electron reduction. 2,3-Bis(dimethylsilyl)-1,1,4,3-tetramethyl-1,4-disila-1,4-dihydronaphthalene (6), which has a half unit of 1, was reacted with lithium metal to give the dilithium salt of the dianion (7). Evidence for an interaction between the Si-H and the Li+ ion of 4 and 7 in both solid state and solution is also given.
• Synthesis and characterization of a cyclobutadiene dianion dilithium salt: Evidence for aromaticity

  A Sekiguchi; T Matsuo; H Watanabe

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 122 23 5652 - 5653 2000年06月 [査読有り]
  
• Anion chemistry of silyl-​substituted π-​electron systems based on four- and five-​membered rings

  Sekiguchi, Akira; Matsuo, Tsukasa

  Yuki Gosei Kagaku Kyokaishi 57 11 945 - 956 1999年11月 [査読有り]
   

  The intramolecular cyclization of silacyclooligoynes with [Mn(CO)(3)(Me-Cp)] produced a variety of silyl-substituted pi-electron systems based on four- and five-membered rings. The silyl-substituted fulvene, dimethylenecyclobutene, [4]radialene derivatives afforded the corresponding dianion species by reduction with lithium metal in polar solvents, whereas the trimethylenecylopentene derivative gave a tetraanion. These anion species were isolated as dilithium or tetralithium salts of the corresponding pi-electron systems. The structures both in crystals and in solution reveal that the silicon atoms attached to the pi-electron systems play an important role for the stabilization oft he resulting polyanions.
• Isolation and characterization of the tetralithium salt of [5]​radialene tetraanion stabilized by silyl groups

  Matsuo, Tsukasa; Fure, Hidetoshi; Sekiguchi, Akira

  Chemical Communications 19 1981 - 1982 1999年10月 [査読有り]
   

  Persilyl-substituted [5]radialene 3 was reacted with lithium metal in THF to yield dark red crystals of the tetralithium salt of tetraanion 4 with a novel ten-center, fourteen pi-electron system stabilized by silyl groups.
• Reduction of the 1,4,5,8-tetrasila-1,4,5,8-tetrahydroanthracene derivative with lithium metal. Isolation and characterization of the tetralithium salt of a tetraanion, and observation of an Si–H···Li+ Interaction

  Matsuo, Tsukasa; Watanabe, Hidetoshi; Ichinohe, Masaaki; Sekiguchi, Akira

  Inorganic Chemistry Communications 2 10 510 - 512 1999年10月 [査読有り]
   

  Treatment of 2,3,6,7-tetrakis(dimethylsilyl) -1,1,4,4,5,5,8,8-octamethyl-1,4,5,8-tetrasila-1,4,5,8-tetrahydroanthracene (1) with lithium metal in diethyl ether yields dark red crystals of the tetralithium salt of the tetraanion, 2, in which the two tetrasilylethylene units are subjected to a two-electron reduction. The molecular structure of 2, determined by X-ray crystallography, is discussed in comparison with that of the neutral molecule 1. Evidence for the interaction between Si-H and the Li+ ion of 2, in both solid state and solution, is also given. (C) 1999 Elsevier Science S.A. All rights reserved.
• Silylacetylene dendrimers: synthesis and characterization

  T Matsuo; K Uchida; A Sekiguchi

  CHEMICAL COMMUNICATIONS 18 1799 - 1800 1999年09月 [査読有り]
   

  The first silylacetylene dendrimers (1G and 2G) with alternating silicon-acetylene units [(SiC=C)(n)] have been synthesized and characterized by spectroscopic methods; the X-ray structure of 1G is reported.
• Silyl-​substituted dilithium salt of fulvene dianion with 6 center​/8 electron π-​system: synthesis and characterization

  Matsuo, Tsukasa; Sekiguchi, Akira; Sakurai, Hideki

  Bulletin of the Chemical Society of Japan 72 5 1115 - 1121 1999年05月 [査読有り]
   

  Treatment of fulvene derivatives bridged by Me2Si-X-SiMe2 chains (2a : X = CH2, 2b : X = O) with lithium metal in THF yields yellow crystals of the dilithium salt of fulvene dianion (3a and 3b) with 6 center/8 electron re-system. The molecular structure of the dianion dilithium 3a has been established by X-ray crystallography. The dianion dilithium 3a has a monomeric structure and forms a contact ion pair (bis-CIP) in the crystal. One of the lithium atoms is located above the center of the five-membered ring by eta(5)-coordination, whereas the other one is bonded to the exo-cyclic carbon atom by eta(2)-coordination, The structural parameters of 3a are discussed in comparison to those of the neutral starting molecule 2a. The structure of 3a in solution has also been discussed on the basis of NMR spectroscopic data. The two lithium ions of 3a are not fixed to the re-skeleton in toluene-d(8), but are fluxional, giving a highly symmetrical bis-CTP structure. The spectral data in THF-d(8) at 298 K also suggest the bis-CIP structure of 3a. However, the lithium ion on the five-membered ring is dissociated to yield an ion pair (CIP-SSIP) at low temperature in THF-d(8), and two dianion species (bis-CIP and CIP-SSIP) were found in THF-d(8).
• Isolation and molecular structure of persilylated [5]radialene: Intramolecular cyclization of a macrocyclic pentayne with Mn(CO)(3)(Me-Cp)

  T Matsuo; H Fure; A Sekiguchi

  CHEMISTRY LETTERS 11 1101 - 1102 1998年11月 [査読有り]
   

  Persilyl-substituted [5]radialene (2) was isolated as orange crystals by the intramolecular cyclization of 3,3,6,6,8,8,11,11, 14,14,16,16,19, 19,21,21-hexadecamethyl-3,6,8, 11,14,16,19, 21-octasilacyclohenicosa-1,4,9,12, 17-pentayne (1) with an excess molar amount of [Mn(CO)(3)(Me-Cp)] by irradiation (lambda > 300 nm) under reflux in THF. The molecular structure and properties of the persilylated [5]radialene 2 are described.
• The First Isolation and Full Characterization of Fulvene Dianion. Synthesis and X-​ray Structure of Dilithium Hexasilylfulvene Dianion

  Matsuo, Tsukasa; Sekiguchi, Akira; Ichinohe, Masaaki; Ebata, Keisuke; Sakurai, Hideki

  Organometallics 17 15 3143 - 3145 1998年07月 [査読有り]
   

  Treatment of hexasilylfulvene (4) with lithium metal in, tetrahydrofuran yields yellow crystals of the dilithium hexasilylfulvene dianion (5). The dilithium hexasilylfulvene dianion (5) has a monomeric structure and forms a contact ion pair (bis-CIP) in the crystals. One of the lithium atoms is located above the center of the five-membered ring, whereas the other one is bonded to the exocyclic carbon atom. The bis-CIP structure determined by X-ray crystallography is maintained in solution.
• Synthesis and characterization of the dilithium salt of the octasilyl[4]​radialene dianion: evidence for a lithium walk on the eight-​center, ten-​electron π-​electron system

  Sekiguchi, Akira; Matsuo, Tsukasa; Sakurai, Hideki

  Angewandte Chemie, International Edition 37 12 1662 - 1664 1998年07月 [査読有り]
  
• Synthesis and reduction of octasilyl[4]​radialene. Structure and dynamic study of [4]​radialene dianion with eight-​center ten-​electron π-​system

  Matsuo, Tsukasa; Sekiguchi, Akira; Ichinohe, Masaaki; Ebata, Keisuke; Sakurai, Hideki

  Bulletin of the Chemical Society of Japan 71 7 1705 - 1711 1998年07月 [査読有り]
   

  The intramolecular reaction of 3,3,5,5,8,8,10,10,13,13,15,15,18,18,20,20-hexadecamethyl-3,5,8,10,13,15,18,20-octasilacycloicosa-1,6,11,16-tetrayne (1) with three molar amounts of [Mn(CO)(3)(Me-Cp)] in THF under photochemical and refluxing conditions produced octasilyl[4]radialene derivative (2). The reaction of 2 with alkali metals (Li, Na, and K) in THF gave dialkali metal salts of the corresponding dianion (4) with an eight-center ten-electron pi-system. The molecular structure of dilithium salt of octasilyl[4]radialene dianion (4a) has been established by X-ray crystallography. The two lithium atoms are located above and below and are bonded to the atoms of the radialene framework to give a bis-CIP structure. The structural parameters of 4a are discussed in comparison to those of 2. The structure of 4a in solution has also been discussed on the basis of NMR spectroscopic data. The two Li+ ions of 4a are not fixed to the pi-skeleton in toluene-d(8), but are fluxional, giving a symmetric structure (bis-CIP) on the NMR time scale. In a solvating medium such as THF-d(8), one of the Li+ ions dissociates to yield an ion pair (CIP and SSIP). Some evidence for the Li+ ion walk on the pi-skeleton is demonstrated.
• Tetraanion Tetralithium with 8 Center​/12 Electron π-​System Stabilized by Silyl Groups. Synthesis and Characterization

  Sekiguchi, Akira; Matsuo, Tsukasa; Akaba, Ryoichi

  Bulletin of the Chemical Society of Japan 71 1 41 - 47 1998年01月 [査読有り]
   

  Reduction of octasilyltrimethylenecyclopentene (2) with lithium metal in tetrahydrofuran yields orange crystals of the tetraanion tetralithium (3) with 8 center/12 electron pi-system. The molecular structure of 3 is unequivocally established by X-ray crystallography. The tetralithium 3 has a monomeric structure and forms contact ion pairs (CIP) in the crystals. The two lithium atoms (eta(5)) are located above and below the center of the five-membered ring, whereas the other two lithium atoms (mu(2)) bonded to the two exocyclic carbon atoms. The structural parameters of 3 are discussed in comparison to that of the neutral starting molecule of 2. The structure of 3 in solution has also been discussed on the basis of NMR spectroscopic data.
• A supercharged anion with a silyl-​substituted eight-​center, twelve-​electron π system: synthesis and characterization of the tetralithium salt of an octasilyl-​substituted trimethylenecyclopentene tetraanion

  Sekiguchi, Akira; Matsuo, Tsukasa; Kabuto, Chizuko

  Angewandte Chemie, International Edition in English 36 22 2462 - 2464 1997年12月 [査読有り]
  
• Intramolecular oligomerization of disilalkylene {-​Me2Si(CH2)​nSiMe2-​} bridged cyclic triacetylenes

  Ebata, Keisuke; Matsuo, Tsukasa; Inoue, Tsuyotoshi; Otsuka, Yuko; Kabuto, Chizuko; Sekiguchi, Akira; Sakurai, Hideki

  Chemistry Letters 12 1053 - 1054 1996年 [査読有り]
   

  Disilalkylene bridged cyclic triacetylenes are prepared and subjected to the transition metal complex mediated reactions. In particular, the reaction with (methylcyclopentadienyl)tricarbonyl-manganese gave a variety of pi-electron systems such as fulvene, dimethylenecyclobutene, and biallene. Structures and reactions of these pi-electron systems are described.
• Persilylated dimethylenecyclobutene dianion dilithium as the first 6C-​8π allyl anion system

  Sekiguchi, Akira; Matsuo, Tsukasa; Ebata, Keisuke; Sakurai, Hideki

  Chemistry Letters 12 1133 - 1134 1996年 [査読有り]
   

  Reduction of persilylated dimethylenecyclobutene with lithium metal in 1,2-dimethoxyethane yields green crystals of persilylated dimethylenecyclobutene dianion dilithium as the first 6C-8 pi allyl anion system. The molecular structure, determined by X-ray crystallography, is discussed in comparison to that of the neutral starting molecule.

書籍

• Chemical Science of π-Electron Systems

  松尾 司 (担当:分担執筆範囲:Part V “Heteroatom-Conjugated π-Electron Systems”, Chapter 23 “π-Conjugated Disilenes and Tetrasilacyclobutadiene”)Springer 2015年
• CSJ Review 12 未来材料を創出するπ電子系の科学

  松尾 司 (担当:分担執筆範囲:Part II 研究最前線、第８節 典型元素不飽和結合のπ電子化学)日本化学会 2013年
• 高次π空間の創発と機能開発

  松尾 司 (担当:分担執筆範囲:第１章 新しいπ電子系化合物の創製、第10節 π共役系ジシレン化合物の構築と機能開発)シーエムシー出版 2013年
• DOJIN ACADEMIC シリーズ3 有機ケイ素化学

  松尾 司; 関口 章 (担当:分担執筆範囲:第３章 多彩な有機ケイ素化合物、第５節 ジシレンとジシリン)化学同人 2013年
• 二酸化炭素の有効利用技術

  第; 章二酸化炭素のエネルギー化技術; 第; 節均一系触媒を用いた二酸化炭素からメタンへの変換技術; 松尾 司 (担当:分担執筆範囲:)㈱サイエンス＆テクノロジー 2010年
• 実験化学講座 第22巻「金属錯体、遷移金属クラスター」

  川口博之; 松尾 司 (担当:分担執筆範囲:第２章 ５族金属錯体 Nb、Ta)丸善 2004年

講演・口頭発表等

• Heavy Cyclobutadienes  [招待講演]

  松尾 司

  International Conference on the Coordination and Organometallic Chemistry of Germanium, Tin and Lead (GTL 2019) 2019年09月 口頭発表（招待・特別）
• Heavy Cyclobutadienes  [招待講演]

  松尾 司

  The 7th Asian Silicon Symposium 2019年07月 口頭発表（招待・特別）
• π-Conjugation between a Si=Si Double Bond and Thiophene Rings  [通常講演]

  松尾 司

  28th International Symposium on the Organic Chemistry of Sulfur 2018年08月
• Heavy Cyclobutadienes, E4(EMind)4 (E = Si and Ge)  [通常講演]

  松尾 司

  The 15th International Symposium on Inorganic Ring Systems (IRIS-15) 2018年06月
• Synthesis, Structural Characterization, and Electronic Properties of Diaryl-substituted Tetrylenes, (Eind)2E: (E = Si, Ge, Sn, and Pb)  [招待講演]

  松尾 司

  2nd International Symposium on Stimuli-responsive Chemical Species for the Creation of Functional Molecules 2017年03月 口頭発表（招待・特別）
• Germanone and Related Compounds  [通常講演]

  松尾 司

  International Conference on the Coordination and Organometallic Chemistry of Germanium, Tin and Lead (GTL 2016) 2016年08月
• π-Conjugated Disilenes Stabilized by Bulky Rind Groups  [招待講演]

  松尾 司

  The 70th Fujihara Seminar 2016年04月 口頭発表（一般）
• Fused-Ring Bulky Rind Groups Producing New Possibilities in Organoelement Chemistry  [招待講演]

  松尾 司

  Institute for Chemical Research International Symposium 2016 (ICRIS’16) 2016年03月 口頭発表（招待・特別）
• Fused-Ring Bulky Rind Groups Producing New Possibilities in Organoelement Chemistry  [招待講演]

  松尾 司

  The 10th Organoelement Chemistry Seminar 2015年07月 口頭発表（招待・特別）
• A New Family of π-Conjugated Silicon Compounds Incorporating the Bulky Rind Groups  [招待講演]

  松尾 司

  2nd International Symposium on Element Innovation 2012年10月 口頭発表（招待・特別）
• π-conjugated silicon compounds stabilized by bulky fused-ring groups  [招待講演]

  松尾 司

  243rd ACS National Meeting 2012年03月 口頭発表（招待・特別）
• A New Family of pi-Conjugated Silicon Compounds Stabilized by the Bulky Rind Groups  [招待講演]

  松尾 司

  The 14th Asian Chemical Congress (14 ACC) 2011年08月 口頭発表（招待・特別）
• π-Conjugated Disilenes and Phosphasilenes Stabilized by Fused-Ring Bulky “Rind” Groups  [招待講演]

  Tsukasa Matsuo

  Pacifichem 2010, Session #35 2010年12月 口頭発表（招待・特別）
• Coplanar π-Conjugated Disilenes and Phosphasilenes Based on the Fused-Ring Bulky “Rind” Groups  [招待講演]

  Tsukasa Matsuo

  Pacifichem 2010, Session #225 2010年12月 口頭発表（招待・特別）
• π-Conjugated Disilenes Stabilized by Fused-Ring Bulky “Rind” Groups  [招待講演]

  Tsukasa Matsuo

  16th Malaysian Chemical Congress 2010年10月 口頭発表（招待・特別）
• π-Conjugated Disilenes and Phosphasilenes Stabilized by Fused-Ring Bulky “Rind” Groups  [招待講演]

  Tsukasa Matsuo

  43rd Silicon Symposium 2010年05月 口頭発表（招待・特別）
• B–B Multiple Bond Species Stabilized by Fused-Ring Bulky Rind Groups  [招待講演]

  Tsukasa Matsuo

  RIKEN International Symposium on Chemistry and Materials Science 2009年11月 口頭発表（招待・特別）
• Development of Bulky Groups Derived from a Fused Ring System for Stabilization of Heavy Unsaturated Bonds  [招待講演]

  Tsukasa Matsuo

  Post ISOS (International Symposium on Organosilicon Chemistry) XV Symposium 2008年10月 口頭発表（招待・特別）
• Fischer-Tropsch Type Reaction with Zirconium Complexes Supported by Tridentate Anisole-bis(sryloxide) Ligands  [招待講演]

  Tsukasa Matsuo

  Pacifichem 2005 2005年12月 口頭発表（招待・特別）

MISC

• ケイ素三員環不飽和化合物の合成と性質

  井上龍二; 大野稜真; 川北翼; 太田圭; 若林知成; ROSAS-SANCHEZ Alfred; 橋爪大輔; 松尾司 ナノ学会大会講演予稿集 20th 2022年
• アルミニウム-アルミニウム二重結合化学種の創製

  松尾 司 Organometallic News 2018 36 2018年 [招待有り]
  
• 炭素とケイ素の不思議（14族元素）

  松尾 司 月刊うちゅう（大阪市立科学館） (2) 2016年02月 [招待有り]
  
• Inside Cover: Activation of Dihydrogen by Masked Doubly Bonded Aluminum Species (Angew. Chem. Int. Ed. 41/2016)

  Koichi Nagata; Takahiro Murosaki; Tomohiro Agou; Takahiro Sasamori; Tsukasa Matsuo; Norihiro Tokitoh Angewandte Chemie - International Edition 55 (41) 12546 2016年
• 縮環型立体保護基によって安定化された発光性ジシレン化合物

  松尾 司 TCIメール 163 1 -6 2014年10月 [招待有り]
  
• Air-Stable Emissive Disilenes Protected by Fused-Ring Bulky “Rind” Groups

  Matsuo Tsukasa TCI MAIL 163 1 -6 2014年
• 典型元素不飽和結合の化学2012

  松尾 司 Organometallic News 83 -88 2013年 [査読有り][招待有り]
  
• Pi-conjugated silicon compounds stabilized by bulky fused-ring groups

  Tsukasa Matsuo ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 243 2012年03月
• 均一系触媒を用いた二酸化炭素からメタンへの変換

  松尾 司 ケミカルエンジニヤリング 57 (3) 202 -207 2012年 [招待有り]
  
• ヘビー級ケトン「ゲルマノン」誕生！！ —ケトンにはない反応性が拓く化学反応の新世界

  松尾 司 化学 67 (10) 45 -50 2012年 [招待有り]
  
• 革新的な汎用性立体保護基の導入による新奇な有機元素化合物の構築と機能開発

  玉尾皓平; 松尾 司 未来材料 11 (7) 50 -56 2011年 [招待有り]
  
• テトラシラシクロブタジエンの初合成から見えてくる化学的知見 —いかに達成したか、そして何が期待されるか

  松尾 司; 鈴木克規; 玉尾皓平 化学 66 (8) 36 -40 2011年 [招待有り]
  
• 縮環型立体保護基によって安定化された高周期典型元素多重結合を含む新規π共役電子系の開発 (特集 立体保護効果を活用した新規機能物質・反応の開発)

  松尾 司; 玉尾 皓平 ファインケミカル 38 (2) 66 -84 2009年02月
• 穏和な条件で一酸化炭素のオリゴマー化に成功

  松尾 司 化学 61 58 -59 2006年 [招待有り]
  
• 光と金属を用いた窒素分子の活性化

  松尾 司 化学と工業 = Chemistry and chemical industry 55 (5) 578 -578 2002年05月
• π電子系アニオン種の化学 - ケイ素基の特性を活用した新しい構造有機化学 -

  松尾 司 化学と工業 = Chemistry and chemical industry 54 (2) 172 -175 2001年02月
• Synthesis and characterization of the dilithium salt of the octasilyl[4]radialene dianion: Evidence for a lithium walk on the eight-center, ten-electron pi-electron system (vol 37, pg 1662, 1998)

  A Sekiguchi; T Matsuo; H Sakurai ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 37 (17) 2292 -2292 1998年09月

産業財産権

• WO2011-099583:立体選択的オレフィン重合用触媒及び立体選択的ポリオレフィンの製造方法  2011年08月18日

  石井 昭彦, 中田 憲男, 戸田 智之, 松尾 司  国立大学法人埼玉大学, 住友化学株式会社  201303056622210375
• 特許第4686702号:ジルコニウムジアラルキル錯体及びそれを用いたアリールアレン類の製造方法  2011年02月25日

  川口 博之, 松尾 司  大学共同利用機関法人自然科学研究機構  201103052538184490
• 特許第4521563号:新規タンタル−ヒドリド錯体及びそれを用いた一酸化炭素の六量体の製造方法  2010年06月04日

  川口 博之, 松尾 司  大学共同利用機関法人自然科学研究機構  201103027544890157
• 特開2009-286760:嵩高い立体保護基を有する新規リン化合物、新規ケイ素−リン二重結合含有化合物およびその製造方法  2009年12月10日

  玉尾 皓平, 松尾 司, 李 保林  独立行政法人理化学研究所  200903059181720948
• 特開2009-215237:新規ケイ素間二重結合含有化合物  2009年09月24日

  玉尾 皓平, 松尾 司, 鈴木 克規  独立行政法人理化学研究所  200903088262178706
• 特開2009-091332:1,2,3,5,6,7−ヘキサヒドロ−s−インダセン骨格を有する化合物  2009年04月30日

  玉尾 皓平, 松尾 司, 冨川 友秀, 鈴木 克規  独立行政法人理化学研究所  200903009180831161
• 特開2009-091333:ケイ素間二重結合含有化合物および蛍光材料  2009年04月30日

  玉尾 皓平, 松尾 司, 冨川 友秀, 鈴木 克規  独立行政法人理化学研究所  200903048772208438
• 特許第4099432号:オレフィン重合用触媒成分及び触媒  2008年03月21日

  川口 博之, 松尾 司, 相原 秀典  日本ポリプロ株式会社  201103012285778435
• WO2007-026831:ジルコニウム・ボラン錯体、及び該錯体を用いたシロキサン類の製造方法  2007年03月08日

  松尾 司, 川口 博之  大学共同利用機関法人自然科学研究機構  200903048344818736
• 特開2006-069986:ジルコニウムジアラルキル錯体及びそれを用いたアリールアレン類の製造方法  2006年03月16日

  川口 博之, 松尾 司  大学共同利用機関法人自然科学研究機構  200903035749907510
• 特開2005-247774:新規タンタル−ヒドリド錯体及びそれを用いた一酸化炭素の六量体の製造方法  2005年09月15日

  川口 博之, 松尾 司  大学共同利用機関法人自然科学研究機構  200903094109306851
• 特開2005-008798:オレフィン重合用触媒成分及び触媒  2005年01月13日

  川口 博之, 松尾 司, 相原 秀典  日本ポリプロ株式会社  200903091666121644
• 特開2004-346268:オレフィン重合用触媒及びそれを用いたオレフィンの重合方法  2004年12月09日

  川口 博之, 松尾 司, 中野 博之, 田谷野 孝夫  日本ポリプロ株式会社  200903073138803891

受賞

• 2012年03月 理化学研究所 理事長感謝状
   

  受賞者: 松尾 司
• 2011年11月 日本化学会 BCSJ賞
   

  受賞者: 松尾 司
• 2010年11月 ケイ素化学協会 第15回ケイ素化学協会奨励賞
   π共役電子系へのケイ素導入効果の多角的研究 

  受賞者: 松尾司
• 2008年08月 理化学研究所 理事長感謝状
   

  受賞者: 松尾 司
• 2008年06月 International Symposium on Organosilicon Chemistry ISOS-XV Post Symposium 高崎 ベストポスター賞
   Homogeneous Reduction of Carbon Dioxide with Hydrosilanes Catalyzed by Zirconium-Borane Complexes 

  受賞者: 松尾司
• 2003年03月 日本化学会 第52回進歩賞
   ケイ素基の特性を活用した四員環及び五員環を機軸とするπ電子系アニオン種に関する研究 

  受賞者: 松尾司
• 2001年03月 日本化学会 BCSJ賞
   

  受賞者: 松尾司
• 2001年03月 日本化学会 第15回若い世代の講演会証
   

  受賞者: 松尾司
• 2001年02月 井上科学振興財団 第17回井上研究奨励賞
   四員環及び五員環を機軸とするケイ素置換π電子系アニオン種に関する研究 

  受賞者: 松尾司
• 2000年12月 筑波学都資金財団 平成12年度教育研究特別表彰
   

  受賞者: 松尾司

共同研究・競争的資金等の研究課題

• 高度に分極した高周期１４族元素－炭素多重結合化学種の合成と反応性の探究

  日本学術振興会：科学研究費助成事業

  研究期間 : 2021年04月 -2024年03月 

  代表者 : 松尾 司

   

  本研究では、高周期１４族元素－炭素多重結合化学種を合成し、特異な結合電子に由来する反応性の探究を通して、典型元素化合物に関する先駆的な研究を格段に発展させることを目的とする。独自に開発したかさ高い「縮環型立体保護基（Rind 基）」を駆使して、高周期１４族元素（ケイ素・ゲルマニウム・スズ）と炭素の二重結合化学種「テトレン」（シレン・ゲルメン・スタニン）を合成し、三重結合化学種「テトリン」（シリン・ゲルミン・スタニン）に変換する。これまでに見いだした先駆的知見を基盤として、学術的にも価値の高い「高周期１４族元素－炭素多重結合化学種」を創り出し、分子構造や化学結合について解明するとともに、高度に分極した電子構造に由来する特異な物性や反応性を探究することを目的とする。 令和４年度は、種々のかさ高さの「縮環型立体保護基（Rind 基）」を有する Ge=Ge 二重結合化学種「ジハロジゲルメン」(Rind)XGe=GeX(Rind) (X = Br, Cl) の合成法を確立し、分子構造を単結晶Ｘ線構造解析により明らかにした。溶液中では Ge=Ge 二重結合が開裂し、ゲルマニウム二価化学種「ハロゲルミレン」(Rind)XGe: (Ge = Br, Cl) として存在することを分光学的手法により明らかにした。 また、種々の「縮環型立体保護基（Rind 基）」を有するスズ二価化学種「ハロスタン二レン」(Rind)XSn: (Ge = Br, Cl) を合成し、Rind 基のかさ高さに応じて結晶中における会合状態が変化することを明らかにした。 「ハロゲルミレン」や「ハロスタン二レン」の存在下、「ハーフペアレント型ジアゾメタン」の光反応について調査した。Ge=C 二重結合をもつ「ブロモゲルメン」が生成することを明らかにし、分子構造を単結晶Ｘ線構造解析により明らかにした。
• 13族元素混合型水素化物の合成と反応性の開拓

  日本学術振興会：科学研究費助成事業

  研究期間 : 2019年04月 -2021年03月 

  代表者 : 松尾 司

   

  本研究では、「アルマボラン(6)」などの新奇な「13族元素混合型水素化物」を設計・合成し、「非対称型水素化物」の分子構造や電子状態を解明するとともに、小分子の活性化などの反応性の開拓を通して、新しい学理「配位アシンメトリー」の創出に貢献することを目的とする。これまでの元素科学研究から見いだした先駆的知見をプラットホームにして、学術的にも価値の高い「非対称型水素化物」を創り出し、従来の対称型水素化物では困難であった小分子の活性化法や異種元素間結合の構築法を開発して、「配位アシンメトリー」の新しいサイエンスに立脚した分子機能の創出に貢献することを目的とする。 令和２年度は、令和元年度に引き続き、種々の「縮環型立体保護基（Rind基）」 を有する「ジボラン(6)」と「ジアルマン(6)」との均一化反応による「アルマボラン(6)」の生成について詳細に調査した。かさ高いEind基を有する「アルマボラン(6)」は溶液中においても安定に存在するのに対し、Eind基よりもかさの大きなMPind基とかさの小さなEMind基を組み合わせた「アルマボラン(6)」は溶液中において不安定であり、「ジボラン(6)」および「ジアルマン(6)」との平衡状態になることを分光学的手法により明らかにした。 また、令和２年度は「アルマボラン(6)」の電子構造について理論計算により調査した。アルミニウム上がプラス、ホウ素上がマイナスに電荷分離した極限構造式の寄与について明らかにし、非対称な三中心二電子結合に関する理論的知見を得た。さらに、「アルマボラン(6)」と強いルイス塩基であるN-ヘテロ環状カルベンとの反応性について調査し、「アルマン・NHC付加体」および「ボラン・NHC付加体」が生成することを突き止めた。「アルマボラン(6)」の還元反応についても調査した。
• 高度に分極した典型元素不飽和化合物の合成と反応性の開拓

  文部科学省：科学研究費補助金（基盤研究(C)）

  研究期間 : 2018年04月 -2021年03月 

  代表者 : 松尾 司
• 高周期14族元素—酸素二重結合化学種の創製と小分子の活性化

  文部科学省：科学研究費補助金（基盤研究(B)）

  研究期間 : 2015年04月 -2018年03月 

  代表者 : 松尾 司
• 無機金属クラスターの反応化学を機軸とした安定小分子の物質変換

  科学技術振興機構：・ 戦略的創造研究推進事業先導的物質変換領域（ACT-C）

  研究期間 : 2013年10月 -2018年03月 

  代表者 : 川口 博之
• 感応性化学種が拓く新物質科学

  日本学術振興会：科学研究費助成事業

  研究期間 : 2012年06月 -2017年03月 

  代表者 : 山本 陽介; 松尾 司; 岩本 武明; 山子 茂; 関口 章; 山口 茂弘; 安倍 学; 池田 浩; 小澤 文幸; 橋本 久子; 山下 誠; 時任 宣博; 吉澤 一成; 杉本 秀樹; 小江 誠司; 井上 豪; 中井 英隆

   

  本領域では、「感応性化学種」という明確な研究コンセプトと、先導的研究者の有機的連携がもたらす多様な研究観点を車の両輪として、真に独創的な異分野融合型の基礎化学研究を推進してきた。その結果、（１） 超原子価16族元素ラジカルの安定化に基づく有機ラジカル電池の創製、（２）中間ジラジカル状態の発見とその得意な電子状態に基づく非線形光学材料への展開、（３）酸素分子を水へと還元する新規ニッケルー鉄触媒の開発、（４）酵素反応の機構を明らかにする時間分解Ｘ線構造解析装置の作成、など、これまでの個別研究では得られなかった新しい物質科学が生まれ、当該学問分野のみならず、関連分野に大きな波及効果をもたらしている。
• ケイ素—炭素三重結合化学種シリンの合成

  文部科学省：科学研究費補助金（挑戦的萌芽研究）

  研究期間 : 2014年04月 -2017年03月 

  代表者 : 松尾 司
• 感応性低配位典型元素化合物の創製と反応

  文部科学省：科学研究費補助金（新学術領域研究）感応性化学種が拓く新物質科学

  研究期間 : 2012年06月 -2017年03月 

  代表者 : 松尾 司
• 熱的に安定なモノ置換チオフェンS-オキシド及びその関連化合物の化学

  日本学術振興会：科学研究費助成事業

  研究期間 : 2013年04月 -2016年03月 

  代表者 : 大谷 卓; 柴田 高範; 松尾 司

   

  チオフェンS-オキシド1やS-イミド2のジエン部位は、容易に[4 + 2]型の二量化反応を起こすため、室温で安定なチオフェンS-オキシドやS-イミドの合成には従来２つ以上の置換基の導入が不可欠であった。今回、３位にEMind基を有するチオフェン4の酸化により対応する一置換チオフェンS-オキシド5を熱的に安定な化合物として得ることに成功した。また、5に様々なアミドを縮合させることにより、熱的に安定な一置換チオフェンS-イミド 6 を得ることにも成功した。EMind基の炭素原子をプローブとして利用した温度可変NMRによって、それらの硫黄原子の反転エネルギーを決定することにも成功した。
• 典型元素不飽和結合化学種の合成と小分子の活性化

  文部科学省：科学研究費補助金（基盤研究(B)）

  研究期間 : 2012年04月 -2015年03月 

  代表者 : 松尾 司
• 低配位汎用元素を鍵とする機能性物質科学の開拓

  科学技術振興機構：戦略的創造研究推進事業さきがけ

  研究期間 : 2011年10月 -2015年03月 

  代表者 : 松尾 司
• 糖の化学的還元反応の開拓

  文部科学省：科学研究費補助金（挑戦的萌芽研究）

  研究期間 : 2011年04月 -2013年03月 

  代表者 : 松尾 司
• 革新的な汎用性立体保護基の導入による新奇な有機元素化合物の構築と機能開発

  文部科学省：科学研究費補助金(特別推進研究)

  研究期間 : 2007年06月 -2012年03月 

  代表者 : 玉尾皓平; 松尾司; 三成剛生

   

  ヒドロインダセン骨格を有するかさ高い縮環型立体保護基(Rind基)の導入により、ジシレンやホスファシレンなど高周期元素不飽和結合を含む新奇なパイ共役電子系物質群を開発した。これらは共平面性に優れた主鎖構造に基づく特異な光物性・電子物性を有しており、有機電子デバイスに応用可能である。また、Rind基の導入により新しい典型元素不飽和化合物の合成にも成功し、実験化学と理論化学の両面から特異な電子構造について解明した。
• カチオン性遷移金属錯体の合成と二酸化炭素の分子変換

  文部科学省：科学研究費補助金(基盤研究(B))

  研究期間 : 2008年04月 -2011年03月 

  代表者 : 松尾司

   

  五員環と六員環が縮環したヒドロインダセン骨格を有するかさ高いアリールオキシド単座配位子などを新たに開発し、ジルコニウムなどの遷移金属錯体を合成して、分子構造を決定した。カチオン性ジルコニウム錯体を触媒として、ヒドロシランを用いた二酸化炭素の化学的還元反応を調査し、従来のキレート型配位子と比べて触媒活性が向上することを見いだした。理論計算により反応機構を調査した。また、オレフィン重合反応を調査した。
• 縮環型立体保護基を用いたケイ素不飽和化学種オリゴマー群の合成および物性の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2007年 -2008年 

  代表者 : 鈴木 克規; 松尾 司; 玉尾 皓平

   

  本研究は新しい共役系機能性分子としての共役系ジシレンオリゴマーの応用へむけた合成法の開発および構造、物性の比較を目標として研究を行った。合成法の開発において重要な中間体となるジブロモジシレンの合成および反応性について詳細に研究を行い、ジブロモジシレンを用いたモノアリール化、ジアリール化反応を見出した。この反応を用いることでこれまでに例のない様々なジシレン群を合成し、その物性について明らかにした。
• 4族遷移金属ポストメタロセン錯体の合成と小分子の活性化

  文部科学省：科学研究費補助金(基盤研究(B))

  研究期間 : 2005年 -2007年 

  代表者 : 松尾司

   

  フェノキシドを基盤としてカルベンやアニソール、アリールチオラートなどを組み合わせた混合型多座配位子を開発し、新規な4族チタン、ジルコニウム錯体を合成して分子構造を解明した。配位子の立体的効果、電子的効果、キレート効果について詳細に検討し、反応活性な金属錯体を設計・合成する上での重要な知見を得た。合成した前周期遷移金属錯体を用いて、水素分子、窒素分子、一酸化炭素、二酸化炭素などの小分子を活性化することに成功した。具体的な研究実績としては、アニソール-フェノキシド混合型三座配位子を有するジルコニウム錯体を合成し、水素と一酸化炭素を穏和な条件(常温・常圧)で活性化して、有機物として選択的にアレンに変換するフィッシャー・トロプシュ型反応を見いだした。一酸化炭素の酸素原子由来である架橋オキソ配位子をケイ素試薬によってシロキサンとして脱離させ、均一系反応による合成サイクルを構築した。また、ジルコニウムアルキル錯体とトリス(ペンタフルオロフェニル)ボランから調製したカチオン性ジルコニウム錯体が、触媒として機能する系を発見し、二酸化炭素とヒドロシランからメタンとシロキサンに変換する新しい均一系触媒反応を開発した。この反応は常温・常圧の穏和な条件で定量的に進行する。ルイス酸性が高くイオン半径の大きな金属反応場を構築し、酸素と親和性の高いケイ素の性質を活かして、二酸化炭素の酸素原子をシリコーンなどの有機ケイ素材料に導入した。さらに、直鎖型および分岐型三座フェノキシド配位子を補助配位子とする5族ニオブ錯体を用いて、窒素分子を六電子還元し、窒素-窒素三重結合を切断した。分岐型三座フェノキシド配位子を有するニオブヒドリド錯体を合成・単離し、水素分子の還元的脱離を伴いながら、窒素分子が還元されて三重結合を切断する新しい反応を見いだした。生成したニトリド錯体の構造と反応性について明らかにした。
• 三重結合を鍵とする多元素分子科学の創製

  科学技術振興機構：科学技術振興調整費（若手任期付研究員支援）

  研究期間 : 2001年06月 -2006年03月 

  代表者 : 松尾司
• シクロブタジエンジアニオンを活用した新しい四員環の合成化学の開拓

  文部科学省：科学研究費補助金(萌芽研究)

  研究期間 : 2004年 -2006年 

  代表者 : 松尾司

   

  平成18年度は、四員環6π電子系化合物であるシクロブタジエンジアニオンの合成化学について引き続き研究するとともに、含ケイ素五員環化合物であるシロール(シラシクロペンタジエン)のジアニオン種に関する研究を行った。1,1-ジメチル-2,5-ジフェニルシロールを1,2-ジメトキシエタン中、金属リチウムと反応させることにより、対応するシロールジアニオンジリチウム錯体を赤色結晶として合成・単離することに成功した。結晶構造では2つのリチウムカチオンがシロール環の上下に位置しており、しかもケイ素とリチウムとの距離は大変短い。リチウムはシロール環とη5型に近い配位構造であることを明らかにした。また、リチウムNMRの研究から、ケイ素-炭素(メチル基)結合のσ*軌道を経由した6π電子系環電流の存在が示唆された。シロールは電子受容性が高く、低いLUMOを有している。LUMOの軌道に2電子充填されたシロールジアニオンでは、6π電子系σ*芳香属性が発現することを見いだした。 また平成18年度は、平成17年度に引き続き、嵩高いアリールオキシド配位子を有する前周期遷移金属錯体の萌芽的研究を行った。オルト位にアダマンチル基を2つ有するアリールオキシド配位子を用いて、4族ジルコニウム錯体に関する研究を行った。ジクロロ錯体の還元反応では、2つのジルコニウム金属がベンゼン環を挟んだ逆サンドイッチ型構造の2核錯体が生成することを見いだした。分子構造を解明するとともに小分子との反応性について調査した。
• 多座配位子による配位空間制御に基づく反応活性高分子錯体の設計と機能化

  日本学術振興会：科学研究費助成事業

  研究期間 : 2005年 -2005年 

  代表者 : 川口 博之; 松尾 司

   

  トリ(2-ヒドロキシフェニル)メタンH_3[O_3]は古くから知られる化合物であるが、これまでに金属錯体の配位子として用いた例は極めて限られている。配位子[O_3]^<3->は次に挙げる3つの配位形態で金属に結合する興味深い化合物である。例えば、配位子のメチン架橋部位の水素原子の方向により、synおよびanti構造が考えられる。特にsyn構造ではメチン水素が金属近傍に存在し、agostic相互作用が強制的に形成される。一方、[O_3]配位子が反応活性な金属に配位した場合、メチン部位で容易にC-H活性化がおこり、新しい4座配位子[O_3C]^<4->が生成する。 Ti(NEt_4)_4とH_3[O_3]を反応させるとsyn型構造をもつ[syn-O_3]Ti(NEt_2)が得られる。錯体[syn-O_3]Ti(NEt_2)の溶液を加熱するとsyn型構造からanti型構造の異性化反応が進行し、[anti-O_3]Ti(NEt_2)を生成する。synおよびanti型アミド錯体[O_3]Ti(NEt_2)とCiSiMe_3の反応からは、共にanti型異性体である[anti-O_3]TiClが得られた。このクロリド錯体のアルキル化反応ではanti型構造は保持され、[anti-O_3]TiR (R=Me,CH_2Ph)を生成する。一方、Zr(CH_2Ph)_4とH_3[O_3]の反応では[syn-O_3]Zr(CH_2Ph)(thf)_2と[O_3C]Zr(thf)_3の混合物を与える。sun型ベンジル錯体は容易に配位子のC-H活性化反応を起こし、[O_3C]Zr(thf)_3を生成する。興味深いことに、anti型構造をもつチタン錯体[anti-O_3]TiRは安定であり、ジルコニウム錯体で観測された分子内メタル化反応を起こさない。
• シクロブタジエンジアニオンの芳香族性の解明と合成試剤への応用

  文部科学省：科学研究費補助金(奨励研究(A), 若手研究(B))

  研究期間 : 2001年 -2002年 

  代表者 : 松尾司

   

  ケイ素置換シクロブタジエンを配位子とするコバルト錯体と金属リチウムとの反応により、ケイ素置換シクロブタジエンジアニオンジリチウム錯体を合成した。また、合成したシクロブタジエンジアニオンのジブロモエタンを用いた二電子酸化反応により、中性の4π電子系化合物であるケイ素置換シクロブタジエンに変換した。これはシクロブタジエンの新規な合成法であり、ヘテロ原子が4つ置換した初めてのシクロブタジエンである。さらに、シクロブタジエンに低温下、光照射することにより、最小のかご型化合物であるケイ素置換テトラヘドランに光異性化することに成功した。これは、ヘテロ元素が4つ置換した初めてのテトラヘドランである。正四面体骨格を有する分子構造をX線結晶構造解析により明らかにした。また、炭素骨格はp性の高い結合でできており、炭素-ケイ素結合は非常にs性の高い結合であることを核磁気共鳴スペクトルを用いた研究により明らかにした。このケイ素置換テトラヘドランは高歪みを有するにもかかわらず、高い熱安定性を有することが特徴である。 また、ケイ素置換シクロブタジエンの種々のアルカリ金属を用いた2電子還元反応について検討し、シクロブタジエンジアニオンジリチウム錯体、ジナトリウム錯体、ジカリウム錯体をそれぞれ合成した。アルカリ金属イオンは周期表を下にいくにつれてイオン性が増大するが、合成したシクロブタジエンジアニオンジアルカリ金属錯体はいずれも安定である。シクロブタジエンジアニオンでは四員環6π電子系による芳香族安定化寄与が大きいことを明らかにした。
• ジルコニウムとボランからなる協奏機能触媒を用いた二酸化炭素からメタンへの変換

  文部科学省：科学研究費補助金(特定領域研究)

  代表者 : 松尾司

委員歴

• 2014年 - 現在   触媒学会   有機金属部会 世話人
• 2013年 - 現在   近畿化学協会   有機金属部会 幹事
• 2006年 - 現在   ケイ素化学協会   理事
• 2016年 - 2017年   ケイ素化学協会   ケイ素化学協会誌 編集委員長
• 2015年 - 2017年   近畿化学協会有機金属部会   OM News編集委員

担当経験のある科目

アドバンスト有機化学近畿大学
有機化学１近畿大学
基礎化学および演習近畿大学
応用無機物質化学特論近畿大学
応用化学実験Ⅰ・Ⅱ近畿大学
物質系工学総論（無機化学分野）近畿大学
基礎ゼミⅠ・Ⅱ近畿大学
分光学Ⅰ近畿大学
アドバンスト無機化学近畿大学
無機化学Ⅱ近畿大学
無機元素化学特論鳥取大学
大学院集中講義筑波大学
大学院集中講義東京工業大学
大学院集中講義早稲田大学
大学院集中講義群馬大学
無機化学早稲田大学

その他のリンク

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