Pt(II) compounds with sulfoxide ligands and crystal structures of complexes of the types I(R2SO)Pt(μ-I)2Pt(R2SO)I and trans-Pt(R2SO)(L)X2 (L = amine, pyridine and pyrimidine)

The crystal structures of several Pt(II) complexes containing sulfoxide ligands are described. The two iodo bridged dimers of the type I(R2SO)Pt(μ-I)2Pt(R2SO)I (where R is ethyl or n-butyl) are twinned structures. The dinuclear species are the trans isomers. Two compounds of the type trans-Pt(DMSO)(amine)X2 were studied by X-ray diffraction methods. The diiodo MeNH2 compound forms H-bonded chains, formed by maximizing the H-bonds between the amine group with the O atom of DMSO and one iodo ligand. The H-bonding pattern is quite different in the dichloro t-BuNH2 complex. In the latter crystal, there are two independent molecules which are H-bonded in pairs. The methyl groups of DMSO and the t-butyl group of the amine are oriented towards the outside of the pairs of molecules, while the H-bonds link the two independent molecules. Again, the amino group forms the maximum H-bonds with the O atom of DMSO and one chloro ligand. The crystal structures of trans-Pt(DMSO)(pyridine)I2 and of trans-Pt(MeBzSO)(pyrimidine)I2 (Bz = benzyl) were also studied. In the pyridine complex, the O atom of DMSO is in the Pt(II) plane by symmetry, while in the pyrimidine compound, the C atom of the –CH3 group is in the Pt(II) plane. The pyridine and the pyrimidine ligands are perpendicular to the Pt(II) square plane. The trans influence of the different ligands is discussed.