Acta Crystallographica Section C

Crystal Structure Communications

Volume 64, Part 3 (March 2008)

metal-organic compounds

jz3123 scheme

Acta Cryst. (2008). C64, m144-m146 [ doi:10.1107/S0108270108004198 ]

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

L. Dahlenburg, F. W. Heinemann, D. Kramer and R. Menzel

Abstract: In the structure of the title compound, [Ir₂Cl₃H₂(C₃₆H₂₈P₂)₂]BF₄·2CH₂Cl₂, the bimetallic cation features a confacial bioctahedral structure that is held together by three bridging chloride ions and is very close to C₂ 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) Å] are significantly longer than those opposite the Ir-P linkages [2.4287 (7)-2.4672 (8) Å]. The Ir-P distances vary between 2.2464 (9) and 2.2565 (8) Å. This study illustrates the usefulness of sterically demanding biaryl-based P₂ ligands in the synthesis of halide-bridged Ir₂ complexes, which are valuable precursors of versatile catalysts for homogeneous C=O hydrogenation.

Formula: [Ir₂Cl₃H₂(C₃₆H₂₈P₂)₂]BF₄·2CH₂Cl₂