Vertex-fused metallaborane clusters: Synthesis, characterization and electronic structure of [(η⁵−C₅Me₅Mo)₃MoB₉H₁₈]

Abstract

The reaction of the [(η⁵-C₅Me₅)MoCl₄] complex with [LiBH₄·THF] in toluene at -70 °C, followed by pyrolysis at 110 °C, afforded dark brown [(η⁵-C₅Me₅Mo)₃MoB₉H₁₈], 2, in parallel with the known [(η⁵-C₅Me₅Mo)₂B₅H₉], 1. Compound 2 has been characterized in solution by ¹H, ¹¹B, and ¹³C NMR spectroscopy and elemental analysis, and the structural types were unequivocally established by crystallographic studies. The title compound represents a novel class of vertex-fused clusters in which a Mo atom has been fused in a perpendicular fashion between two molybdaborane clusters. Electronic structure calculations employing density functional theory yield geometries in agreement with the structure determinations, and on grounds of density functional theory calculations, we have analyzed the bonding patterns in the structure.