Oxo transfer and metal oxidation in the reaction of [Ru(PPh3)3Cl2] with m-chloroperbenzoic acid: structure of [Ru(PPh3)2(m-ClC6H4CO2)Cl2]

Abstract

One mol and 0.5 mol of peracid are consumed for oxo transfer to PPh₃ and oxidation of metal, respectively, in the reaction of [Ru(PPh₃)₃Cl₂] with m-ClC₆H₄CO₃H. The active oxo-transfer agent is metal-bound peracid. After oxo transfer the carboxylate residue remains chelated to the metal centre as shown by an X-ray structure determination of the product [Ru(PPh₃)₂(m-ClC₆H₄CO₂)Cl₂](1). The trans, cis, cis-RuP₂O₂Cl₂ co-ordination sphere has two-fold symmetry. Its e.s.r. and near-i.r. spectra are in agreement with the energy order d_xy > d_xz′, d_yz. The complex undergoes one-electron quasi-reversible reduction but only at low potentials (E₂₉₈°–0.40 V vs. saturated calomel electrode).