Complexes based on asymmetrically substituted pyridine–dithiolene ligands [M(4-pedt)2] (M = Au, Cu, Ni; 4-pedt = 1-(pyridin-4-yl)-ethylene-1,2-dithiolate): Synthesis, structure and physical properties

The monoanionic Ni, Au and Cu bisdithiolene complexes based on the 1-(pyridin-4-yl)-ethylene-1,2-dithiolate were prepared and isolated as [PPh4]+, [n-Bu4N]+ and [Na(18C6)]+ salts which were characterised by single-crystal X-ray diffraction, cyclic voltammetry, EPR and magnetic susceptibility measurements. All the complexes adopt a square planar coordination geometry with a trans arrangement of the substituent pyridine rings whose planes are rotated from 13° to 33° relatively to the central MS4 core. The C–C and C–S bond lengths are consistent with ene-1,2-dithiolate form of the ligand and MIII oxidation state. The Ni complexes are paramagnetic with an effective magnetic moment of ∼1.7 BM.

Graphical abstractThe synthesis of M(4-pedt)2 complexes of nickel, copper and gold obtained as tetrabutylammonium, tetraphenylphosphonium or sodium 18-crown-6 ether salts are described and these compounds are characterised by single-crystal X-ray diffraction, cyclic voltammetry, EPR and magnetic susceptibility measurements.Figure optionsDownload full-size imageDownload as PowerPoint slide