Electronic, geometrical, and thermochemical studies on group-14 element-diruthenaborane cluster compounds: a theoretical investigation

Abstract

Density functional theory (DFT) calculations were used to probe the reaction of the diruthenaborane nido-[1,2-(Cp*RuH)₂B₃H₇] (Cp* = η⁵-C₅Me₅), (1) with MeC ≡ CMe to form the major product nido-[1,2-(Cp*Ru) ₂ (μ-H)(μ-BH₂)-4,5-Me₂-4,5-C₂B₂H₄] (2) along with minor product nido-(Cp*Ru)₂-4,5-Me₂-4,5-C₂B₂H₆ (3). The structural features of the other related diruthenacarboranes, nido-(Cp*Ru)₂-4,5-Me₂-4,5-C₂B₂H₆ (4) and closo-1,2-(Cp*RuH)₂-4,5-Me₂-4,5-C₂B₃H₃ (5), were also studied. Since metallaheteroboranes with p-block group-14 elements are rare, we extend our DFT studies to explore the reaction of 1 with heavier group-14 alkyne analogs, RE ≡ ER (E = Si, Ge, and Sn; R = alkyl or aryl groups). The geometrical and electronic structures of the products nido-[1,2-(Cp*Ru)₂ (μ-H)(μ-BH₂)-4,5-Me₂-4,5-E₂B₂H₄] (E = Si (6), Ge (7), Sn (8)) are described and compared with the ruthenacarborane analog, nido-[1,2-(Cp*Ru)₂ (μ-H)(μ-BH₂)-4,5-Me₂-4,5-C₂B₂H₄] species, 2. The computed energetics and the geometries support the feasibility of the reaction and the stability of the products. NBO analysis was performed to delve further into the nature of the bonding in this kind of clusters.