Chemistry of ruthenium σ-borane complex, [Cp∗RuCO(μ-H)BH₂L] (Cp∗ = η⁵-C₅Me₅; L = C₇H₄NS₂) with terminal and internal alkynes: structural characterization of vinyl hydroborate and vinyl complexes of ruthenium

Abstract

The chemistry of ruthenium–borane complex, [Cp∗RuCO(μ-H)BH₂L] (Cp∗ = η⁵-C₅Me₅; L = C₇H₄NS₂), 1 with various alkynes has been explored. Photolysis of 1 with alkynyl-Grignard, [HC≡CMgBr] in toluene led to the isolation of vinyl hydroborate complex [Cp∗Ru(μ-H)BH{HC=CH₂}L], 2a as a sole product. Compound 2a can be viewed as a ruthenium–borate complex with an ethylene moiety. Further, the chemistry of 1 with various internal and terminal alkynes has been performed in photolytic conditions. Photolysis of 1 with [RC≡CR] (R = CO₂Me) yielded vinyl hydroborate complex [Cp∗Ru(μ-H)BCl{RC=CR}L], 2b. Terminal alkynes [HC≡CR] (R = Ph or CO₂Me) under the same reaction conditions led to the isolation of metal vinyl complexes [Cp∗Ru(CO)(C₂HR)(L)], 3a and 3b (3a: R = Ph; 3b: R = CO₂Me). In addition, DFT calculations were carried out to analyze the bonding and electronic structures of these new compounds.