The steric effect of o-tolyl ligand on the fluxionality behavior of some binuclear organoplatinum(II) complexes with bis(diphenylphosphino)methane as bridging ligand

A series of binuclear organoplatinum(II) complexes of general formula cis ,cis -[R2Pt(μ-SMe2)(μ-dppm)Pt(o -MeC6H4)2], 3a–3d, in which R = Ph, p -MeC6H4, m -MeC6H4 or p -MeOC6H4, were prepared by the reaction of monomeric precursors [Pt(o -MeC6H4)2(dppm)] and cis -[PtR2(SMe2)2]. The binuclear dialkyl analogs, in which R = Me (3e) or R2 = {(CH2)4} (3f), were prepared by the reaction of cis -[Pt(o -MeC6H4)2 (SMe2)2] and [PtR2 (dppm)]. The complexes were fully characterized by multinuclear (1H, 13C, 31P, 195Pt) NMR spectroscopy each as a mixture of syn and anti isomers (depending on the relative orientations of Me substituents on o -tolyl ligands) and each isomer was shown to have a rigid structure. Other binuclear analogs View the MathML sourcecis,cis-[R2Pt(μ-SMe2)(μ-dppm)PtR2′], 3g–3j, in which R is a less steric demanding aryl groups m -MeC6H4 or p -MeOC6H4, and R′ = Me or View the MathML sourceR2′={(CH2)4}, were prepared by the reaction of cis -[PtR2(SMe2)2] and View the MathML source[PtR2′(dppm)], and shown to have fluxional structures.