Unsupported Metal Chain Complex: Synthesis, Characterization and EHMO Study Involving the Tetraosmium Complex [Os2(CO)5(thd)2]2

[[abstract]]Metal carbonyl complex Os3(CO)12 reacts with a hexane solution of (thd)H, thd = 2,2-dimethyl-3,5-heptanedionate, in a sealed autoclave at 190 °C to afford the Os4 metal chain complex [Os2(CO)5(thd)2]2 (1), isolated from repeated recrystallization in air. Treatment of 1 with CO at room temperature gives the Os2 metal complex [Os2(CO)6(thd)2] (2) through reversible cleavage of the central Os−Os bond. EHMO calculation has been carried out to explain the involvement of a short−long−short Os−Os···Os−Os array.[[fileno]]2010311010061[[department]]化學