Oishi Masataka, Oshima Masato, Suzuki Hiroharu
Graduate School of Science and Engineering, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
Inorg Chem. 2014 Jul 7;53(13):6634-54. doi: 10.1021/ic500258g. Epub 2014 Jun 10.
Zr-Ir hydrido complexes with ansa-(cyclopentadienyl)(amide) as the supporting ligand in the zirconium fragment, e.g., (L(1)ZrR)(CpIr)(μ-H)3 [L(1) = Me2Si(η(5)-C5Me4)(N(t)Bu), R = Cl (5), Ph (7), Me (10), alkyl, and aryl] were designed, synthesized, and isolated as tractable early-late heterodinuclear complexes. Despite the presence of the three supporting hydride ligands, Zr-Ir distances in the crystal structures of 5, alkyl, and aryl complexes [2.74-2.76 Å] were slightly longer than the sum of the element radii of Zr and Ir [2.719 Å]. These hydrocarbyl complexes displayed the thermolytic C-H activation of a variety of aromatic compounds and several organometallic compounds. Also, the substrate scope and limitation in the Zr-Ir system were studied. The regiochemical outcomes during the C-H activation of pyridine derivatives and methoxyarenes suggested the in situ generation of a Lewis acidic active intermediate, i.e., (L(1)Zr)(CpIrH2) (III). The existence of III and relevant σ-complex intermediates {L(1)Zr(η(2)-R-H)}(Cp*IrH2) (IIR) (R = Me, Ph) in the ligand exchange was demonstrated by the direct isolation of a Et3PO-adduct of III (39b) from 7 and kinetic studies. The structure of the direct Zr-Ir bonds in IIPh, IIMe, III, and 39b were probed using computational studies. The unprecedented strong M-M' interactions in the early-late heterobimetallic (ELHB) complexes have been proposed herein.
以桥联（环戊二烯基）（酰胺）作为锆片段中的支撑配体的Zr-Ir氢化物配合物，例如(L(1)ZrR)(CpIr)(μ-H)3 [L(1) = Me2Si(η(5)-C5Me4)(N(t)Bu)，R = Cl (5)，Ph (7)，Me (10)，烷基和芳基]，被设计、合成并分离为易于处理的早-晚异双核配合物。尽管存在三个支撑氢化物配体，但5、烷基和芳基配合物晶体结构中的Zr-Ir距离[2.74 - 2.76 Å]略长于Zr和Ir的元素半径之和[2.719 Å]。这些烃基配合物表现出对多种芳香族化合物和几种有机金属化合物的热解C-H活化作用。此外，还研究了Zr-Ir体系中的底物范围和局限性。吡啶衍生物和甲氧基芳烃C-H活化过程中的区域化学结果表明原位生成了一种路易斯酸性活性中间体，即(L(1)Zr)(CpIrH2) (III)。通过从7直接分离出III的Et3PO加合物(39b)和动力学研究，证明了配体交换中III和相关σ-配合物中间体{L(1)Zr(η(2)-R-H)}(Cp*IrH2) (IIR)（R = Me，Ph）的存在。使用计算研究探测了IIPh、IIMe、III和39b中直接Zr-Ir键的结构。本文提出了早-晚异双金属（ELHB）配合物中前所未有的强M-M'相互作用。
