Theoretical and experimental investigations on hypoelectronic heterodimetallaboranes of group 6 transition metals

Abstract

Density functional theory (DFT) has been used to probe the bonding and electronic properties of dimolybdaborane [(Cp*Mo)₂B₅H₉], 1 (Cp* = η⁵-C₅Me₅), and several other heterodimolybdaborane clusters, such as [(Cp*Mo)₂B₅(μ₃-OEt)H₇] (2), [(Cp*Mo)₂B₅(μ₃-OEt)(n-BuO)H₆] (3), [(η⁵-C₅H₅W)₂B₄H₄S₂] (4), and [(Cp*Mo)₂B₄H₄E₂] (5–7, where, for 5, E = S, for 6, E = Se, and for 7, E = Te). The DFT results were also used to address some key points such as (i) the metal–metal bond length, (ii) the location and number of bridging and terminal hydrogen atoms, (iii) the molecular orbital analysis, and (iv) the assignment of ¹¹B and ¹H NMR chemical shifts. These studies further provide meticulous insight into similarities and differences between various dimetallaborane clusters 1–7. In addition, the crystal structures of 5 and 7 are reported, which come on top of the already existing literature of dimetallaboranes and support the theoretical findings.