102307-83-5Relevant academic research and scientific papers
Transformation of a terminal to a bridging carbonyl ligand accompanied by Ir-Ir bond cleavage: An example of transmission of electronic effects from one metal center to another
Cowie, Martin,Vasapollo, Giuseppe,Sutherland, Bruce R.,Ennett, Jimmie P.
, p. 2648 - 2653 (2008/10/08)
The alkyne-bridged complex [Ir2Cl2(CO)(μ-DMA)(DPM)2] (DMA = dimethyl acetylenedicarboxylate, DPM = bis(diphenylphosphino)methane) reacts with 1 equiv of CO, PMe3, P(OMe)3, or NCMe to give one of two types of species. Reaction with CO yields the complex [Ir2Cl2(CO)2(μ-DMA)(DPM)2], in which both carbonyl groups are terminally bound, one to each metal. However, reaction with L = PMe3, P(OMe)3, or NCMe yields the adducts [Ir2Cl2L(μ-CO)(μ-DMA)(DPM)2], in which the carbonyl group bridges the metals with no accompanying Ir-Ir bond. A rationalization of the different structures observed with the different ligands is presented. The structure of the acetonitrile adduct was determined by X-ray techniques. This species crystallizes in space group P21/c with a = 13.060 (5) A?, b = 15.742 (2) A?, c = 30.756 (5) A?, β = 92.75 (2)°, V = 6315.9 A?3, and Z = 4. On the basis of 5807 unique observations and 418 parameters varied, the structure converged at R = 0.051 and Rw = 0.073. The long metal-metal separation of 3.4580 (7) A? results in a geometry at the bridging carbonyl ligand that is reminiscent of sp2 hybridization (Ir-C(O)-Ir angle of 119.4 (6)°).
