Kharasch addition catalysed by half-sandwich ruthenium complexes. Enhanced activity of ruthenacarboranes

Ruthenium complexes of the type [RuH(η5-CB)(PPh3)2] {CB is a monoanionic charge-compensated carborane ligand such as [9-SR2-7,8-C2B9H10]− and [9-SR2-7-CH3-7,8-C2B9H9]−} efficiently catalyse the Kharasch addition of CCl4 across olefins and, with maximum total turnover numbers of 9000 and initial turnover frequencies of 1900 h−1 at 40°C, highly surpass their Ru–Cp# analogues in these reactions.