Synthesis and crystal structure of unsymmetrical trinuclear nickel(0) complexes with the 1,3-butadiynes in the monodentate and μ2-η2,η2-bridging mode [Ni3(L)(cod)3] (L=tmsb and dpbd)

Article abstract of DOI:10.1016/0277-5387(95)00211-A

Novel trinuclear nickel(0) complexes [Ni3(L)(cod)3] (cod=1,5-cyclooctadiene) with L=1,4-bis(trimethylsilyl)-1,3-butadiyne (1) and 1,4-diphenyl-1,3-butadiyne (2) have been prepared and their structures have been crystallographically determined. These trinuclear nickel(0) complexes are thefirst unsymmetrical trinuclear complexes with the 1,3-butadiynes in the monodentate and μ2-η2,η2-coordination mode. The acetylenic C -C distance of 1.343(7) and 1.33(2) ? for 1 and 2 in the μ2-η2,η2-bridging mode is rather larger than that of 1.267(7) and 1.26(2) ? for 1 and 2 in the monodentate mode, indicative of a larger contribution of π back donation. The weak ν(C.ident.C) frequency was given at 1784 and 1782 cm**-1 for 1 and 2, respectively.