Synthesis and reactivity of platinum(II) triphenylphosphino complexes with aromatic aldoximes

trans-[Pt(μ-Cl)Cl(PPh3)]2 reacted with arylaldoximes in 1,2-dichloroethane to afford [PtCl2(PPh3){N(OH)=CHAr}] (Ar = 3,4-dimethoxyphenyl, 1-naphthyl, 9-anthryl) where aldoxime ligands are N-coordinated to platinum. The obtained complexes are soluble in chlorinated solvents, where they afford equilibrium mixtures of cis,trans and/or (E),(Z) isomers. Equilibria in solution were studied by 31P-NMR spectroscopy and solid state structural data were obtained by single crystal X ray diffraction studies. The reactivity of [PtCl2(PPh3){N(OH)=CHAr}] complexes with basic aqueous solutions was studied, under liquid-liquid phase transfer catalysis conditions. The outcome of the reaction depends on the stereochemistry of the precursors: cis,(Z)-isomers promptly undergo cyclization to the corresponding dinuclear derivatives [Pt{μ-(2-N,O)}- {N(O)=CHAr}Cl(PPh3)]2, where two aldoximate ligands symmetrically bridge two metal centers.