Synthesis and Structures of the μ-Vinylidene Binuclear Nickel Complexes [Ni2(μ-CCH2)(dmpm)2Cl2] and [Ni2(μ-CCH2)(dppm)2Br2]: Comparison of the Electronic Structures of Nickel A-Frames

摘要: The reaction of bis(cyclooctadiene)nickel(0) with bis(dimethylphosphino)methane (dmpm) and 1,1-dichlorovinylidene in THF yields the vinylidene-bridged binuclear nickel A-frame complex [Ni2(μ-CCH2)(dmpm)2Cl2] (1a). structure 1a was determined by X-ray crystallography. Ni−Ni separation is 2.898(2) A, vinylidene carbon−carbon bond distance 1.35(2) A. bis(diphenylphosphino)methane (dppm) bridged μ-vinylidene [Ni2(μ-CCH2)(dppm)2Br2] (2b) also 2.874(2) A for 2b comparable to that 1a. series A-frames substituted terminal ligands [Ni2(μ-CCH2)(PR2CH2PR2)2X2] (X = Cl, Br, I, R Me; X NCS, OCN; Ph) were prepared characterized. different bridging [Ni2(μ-CE)(dppm)2Cl2] (E O, NPh) examined. Extended Huckel molecular orbital (EHMO) calculations indicate HOMO these complexes is...