The displacement of one of two dithiolene ligands in bis(dithiolene) complexes of Ni, Pd and Pt by two equivalents of phosphine has long been known. However, metal complexes with bis(chelating) phosphine ligands, one of the two phosphine chelates being open and not coordinated to any metal ion, have been little studied. We have examined the direct substitution of dithiolene ligand from [M(S2C2R2)2] (M = Ni, Pd or Pt; R= -C6H4-p-OMe, Ph or Me) with 1,2,4,5-tetrakis(diphenylphosphino)benzene (tpbz) ligand in CH2Cl2 to afford [(tpbz)M(S2C2R2)]. All compounds are air-stable and can be purified by column chromatography on silica using CH2Cl2-hexanes mixtures to afford yields of ~50%. Crystals of these metal complexes were obtained from DCM/Et2O by vapor diffusion methods. Structures obtained by X-ray diffraction reveal square planar or distorted square planar geometries. Electrochemistry of [(tpbz)Ni(S2C2Ph2)] showed a fully reversible oxidation, a quasi reversible oxidation and a fully reversible reduction. This behavior was little affected by the identity of the metal or the dithiolene substituent, R. In column chromatography [(R2C2S2(tpbz)M(S2C2R2)] were obtained as a byproducts using CH2Cl2-THF solvents.

Group 10 dithiolene compounds with an open-ended 1,2,4,5-Tetrakis(diphenylphosphino)benzene ligand: Synthesis, structure, properties

255th National Meeting (2018)

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