LAUSR

Abstract Two new dirhenium compounds Re2(CO)8[μ-η2-1,3-C2B10H10(1-SCH3)](μ-H), 1 (3.2 % yield) and Re2(CO)8[μ-η2-1,4-C2B10H10(1-SCH3)](μ-H), 2 (31 % yield) were obtained from the reaction of closo-o-(1-SCH3)C2B10H11 with Re2(CO)8[μ-η2-C(H)C(H)Bun](μ-H) in an octane solution heated to reflux. Both compounds contain a C2B10H10(1-SCH3) ligand that bridges the pair of rhenium atoms by the sulfur atom and one of the boron atoms of the carborane cage. The Re – B bonds were formed by oxidative addition of one of the B – H bonds of the carborane to one of the Re atoms. The isomers differ by which boron atom, B(3) for 1 and B(4) for 2, has been added to the Re atom. Compound 1 was isomerized to 2 by heating to 107 °C, but 2 does not isomerize back to 1. A mechanism for the isomerization that involves a reductive-elimination of B(3) and the hydride ligand of 1 followed by an oxidative-addition of the neighboring B(4)-H bond to form 2 is proposed. The new compound Re2(CO)7[μ-η3-C2B10H9(1,2-(SCH3)2](μ-H), 3 was obtained in 38% yield from the reaction of [o-1,2-(SCH3)2]C2B10H10 with Re2(CO)8[μ-η2-C(H)C(H)Bun](μ-H) in an octane solution heated to reflux for 2h. The bridging C2B10H9(1,2-(SCH3)2 ligand is coordinated to one of the rhenium atoms by the two sulfur atoms at one of the Re atoms and the carborane boron atom B(3) also underwent cleavage at the B(3) – H bond to form the Re – B(3) bond to the other Re atom.