Homo- and hetero-dinuclear hydride-bridged complexes containing cyclo-octadiene: the crystal and molecular structure of [(η4-C8H12)Ir(µ-H)(µ-Cl)IrH2(PPh3)2]

Abstract

The reaction of [IrH₅(PPh₃)₂] with [{M(cod)Cl}₂](M = Rh or Ir, cod = cyclo-octa-1,5-diene) gives the dinuclear complexes [(η⁴-C₈H₁₂)M(µ-H)(µ-Cl)IrH₂(PPh₃)₂]. The di-iridium compound has been subjected to an X-ray analysis which establishes that the iridium(I) atom adopts a square-planar co-ordination geometry while the iridium(III) atom is in a pseudo-octahedral environment if the direct Ir–Ir interaction is ignored. The two Ir atoms are bridged by a hydride and a chloride ligand. The Ir–Cl bridge is highly asymmetric [Ir(1)–Cl(1) 2.352(8), Ir(2)–Cl(1) 2.534(8)Å], and this asymmetry is discussed in terms of the relative trans effect of the ligands present.