Reaction of the Alkylindium(I) Compound In4[C(SiMe3)3]4 with Octacarbonyldicobalt: Bridging of the Co-Co Bond by one or two In-C(SiMe3)3 Groups

Abstract
tetrahedra‐Tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) reacts with octacarbonyldicobalt to yield two products, depending on the stoichiometric ratio of the starting compounds: By replacement of one bridging carbonyl group a dicobalt monoindium derivative 2 is formed, which contains a CoCo bond [256.81(5) pm] bridged by one carbonyl and one monoalkylindium group. While 2 is a monomer in benzene solutions, it dimerizes in the solid state by an interaction of the oxygen atom of the bridging carbonyl group to the coordinatively unsaturated In atom of a second molecule across a center of symmetry. Another compound (3) is formed by the replacement of both bridging carbonyl ligands, which exhibits a strongly distorted Co2In2 tetrahedron with normal CoIn bond lengths of 253.44(6) pm, but long CoCo [280.14(6) pm] and InIn distances [336.18(6) pm].