syn-Tri-μ-chlorido-bis{[(R,R)/(S,S)-2,2′-bis(diphenylphosphino)-1,1′-biphenyl]hydridoiridium(III)} tetrafluoridoborate dichloromethane disolvate

Abstract

In the structure of the title compound, [Ir(2)Cl(3)H(2)(C(36)H(28)P(2))(2)]BF(4) x 2 CH(2)Cl(2), the bimetallic cation features a confacial bioctahedral structure that is held together by three bridging chloride ions and is very close to C(2) symmetric. The hydrides are in a syn orientation (trans to the same halide bridge), and the chelating bis(phosphine) atropisomers display a racemic (R,R)/(S,S) configuration. Because of the high trans-bond-weakening influence of the hydride ligands, the Ir-Cl bonds trans to Ir-H [2.5262 (7) and 2.5365 (7) A] are significantly longer than those opposite the Ir-P linkages [2.4287 (7)-2.4672 (8) A]. The Ir-P distances vary between 2.2464 (9) and 2.2565 (8) A. This study illustrates the usefulness of sterically demanding biaryl-based P(2) ligands in the synthesis of halide-bridged Ir(2) complexes, which are valuable precursors of versatile catalysts for homogeneous C=O hydrogenation.