Redox properties of [IrCl4(PMe2Ph)2] : the synthesis of halide-bridged mixed-metal mixed-valence complexes and the crystal and molecular structure of [(Me3As)ClPd(µ-Cl)2IrCl2(PMe2Ph)2]

Abstract

The potential of [IrCl₄(PMe₂Ph₂] as a one-electron oxidising agent in organometallic chemistry has been evaluated. In complementary redox reactions with metallocenes, salts of the general form [M(η-C₅H₅)₂][IrCl₄(PMe₂Ph)₂](1) are formed. In non-complementary reactions with platinum(0) and palladium(II) complexes some interesting mixed-metal mixed-valence complexes of the type [Ph₃P)₂Pt(µ-Cl)₂IrCl₂(PMe₂Ph)₂][IrCl₄(PMe₂Ph)₂](2) and [(Me₃As)ClPd(µ-Cl)₂IrCl₂(PMe₂Ph)₂](3) are formed. Complex (3) has been characterised by single-crystal X-ray diffraction studies. It crystallises in the space group P2₁/n of monoclinic symmetry in a cell of dimensions a= 12.218(2), b= 13.187(2), c= 17.832(2)Å, β= 91.80(1)° and Z= 4, the final R and R′ being 0.046 and 0.051 respectively based on full-matrix refinement of 167 variables and 4 273 observations. This structural determination confirms that (3) contains an octahedral iridium(III) unit linked to a square-planar palladium fragment by means of chloride bridges.