The reactions of carbon monoxide with series of dirhenium species [Re 2Cl 4(PMe 2Ph) 4] n+ (n = 0, 1, 2) possessing rhenium—rhenium bond orders of 4, 3.5 and 3

Abstract

The complexes [Re 2Cl 4(PMe 2Ph) 4](PF 6), n, where n = 1, 1 or 5, which possess ReRe multiple bonds of orders 3, 3.5 and 4, respectively, react with carbon monoxide in 2-methoxyethanol to afford the reductive cleavage product ReCl(CO) 3(PMe 2Ph) 2 in high yield. In other solvents (ethanol and toluene), these reactions are complicated by competing side reactions which can result in redox chemistry at the dirhenium units without the incoporation of CO into the products. The reactions in ethanol and toluene lead to the formation of Re 2Cl 5(PMe 2Ph) 3, Re 2Cl 6(PMe 2Ph) 2, trans-ReCl 4(PMe 2Ph) 2, ReCl(CO) 2(PMe 2Ph) 3 and/or ReCl 3(CO)(PMe 2Ph) 3, in addition to ReCl(CO) 3(PMe 2Ph) 2, depending upon the reaction conditions. The electrochemical properties of the carbonyl containing prosducts ReCl(CO) 2(PMe 2Ph) 3, ReCl(CO) 3(PMe 2Ph) 2 and ReCl 3(CO) 2(PMe 2Ph) 3, as well as those of the previuosly described rhenium(II) dicarbonyl complex ReCl 2(CO) 2(P-n-Pr 3) 2, have been studied using the cyclic voltammetry technique.