Coordination chemistry of thioether-carboranes in polynuclear metal carbonyl cluster complexes. B-H activation of thioether-carboranes by dirhenium carbonyl complexes

Publication date: 15 June 2018 Source:Journal of Organometallic Chemistry, Volume 865 Author(s): Richard D. Adams, Joseph Kiprotich 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 cleavag...

Source: Journal of Organometallic Chemistry - May 19, 2018 Category: Chemistry Source Type: research