Ring opening of 3,3,4,4-tetracyano-2,2-bis(triphenylarsine)-1-oxa-3-platinacyclobutane promoted by various phosphines

In the presence of added ligand, (PMe2Ph, PEt3, PMePh2 and PEt2Ph) the title compound undergoes ligand exchange and ring opening to give compounds of the type {L2Pt(CN)[OC(CN)C(CN)2]} having a trans configuration. A spectrophotometric kinetic study was carried out in CH2Cl2 and C2H5OH and the rate found to be proportional to the concentration of added phosphine. A linear relation between the second order rate constants and the cone angles of entering ligands points to the dominance of steric effects.