Ishihara Kodai, Araki Yuna, Tada Mizuki, Takayama Tsutomu, Sakai Yoichi, Sameera W M C, Ohki Yasuhiro
Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan.
Chemistry. 2020 Aug 3;26(43):9537-9546. doi: 10.1002/chem.202000104. Epub 2020 Jul 20.
Two transition-metal atoms bridged by hydrides may represent a useful structural motif for N activation by molecular complexes and the enzyme active site. In this study, dinuclear Mo -Fe complexes with bridging hydrides, Cp Mo(PMe )(H)(μ-H) FeCp* (2 a; Cp =Cp*=C Me , 2 b; Cp =C Me H), were synthesized via deprotonation of Cp Mo(PMe )H (1 a; Cp =Cp*, 1 b; Cp =C Me H) by CpFeN(SiMe ) , and they were characterized by spectroscopy and crystallography. These Mo-Fe complexes reveal the shortest Mo-Fe distances ever reported (2.4005(3) Å for 2 a and 2.3952(3) Å for 2 b), and the Mo-Fe interactions were analyzed by computational studies. Removal of the terminal Mo-H hydride in 2 a-2 b by [Ph C] in THF led to the formation of cationic THF adducts [Cp Mo(PMe )(THF)(μ-H) FeCp] (3 a; Cp =Cp*, 3 b; Cp =C Me H). Further reaction of 3 a with LiPPh gave rise to a phosphido-bridged complex CpMo(PMe )(μ-H)(μ-PPh )FeCp (4). A series of Mo-Fe complexes were subjected to catalytic silylation of N in the presence of Na and Me SiCl, furnishing up to 129±20 equiv of N(SiMe ) per molecule of 2 b. Mechanism of the catalytic cycle was analyzed by DFT calculations.
由氢化物桥连的两个过渡金属原子可能是分子配合物和酶活性位点激活氮的一种有用的结构基序。在本研究中，通过用CpFeN(SiMe₃)₂对Cp₂Mo(PMe₃)H（1a；Cp = Cp，1b；Cp = C₅Me₄H）进行去质子化反应，合成了具有桥连氢化物的双核Mo - Fe配合物Cp₂Mo(PMe₃)(H)(μ - H)FeCp*（2a；Cp = Cp* = C₅Me₅，2b；Cp = C₅Me₄H），并通过光谱学和晶体学对其进行了表征。这些Mo - Fe配合物展现出了有史以来报道的最短Mo - Fe距离（2a为2.4005(3) Å，2b为2.3952(3) Å），并且通过计算研究对Mo - Fe相互作用进行了分析。在四氢呋喃中用[Ph₃C]⁺除去2a - 2b中的末端Mo - H氢化物，导致形成阳离子四氢呋喃加合物[Cp₂Mo(PMe₃)(THF)(μ - H)FeCp*]⁺（3a；Cp = Cp*，3b；Cp = C₅Me₄H）。3a与LiPPh₂进一步反应生成了一个磷桥连配合物CpMo(PMe₃)(μ - H)(μ - PPh₂)FeCp（4）。一系列Mo - Fe配合物在Na和Me₃SiCl存在下进行氮的催化硅氢化反应，每分子2b最多可提供129±20当量的N(SiMe₃)₃。通过密度泛函理论（DFT）计算分析了催化循环的机理。
