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

Abstract

The monoanionic Ni, Au and Cu bisdithiolene complexes based on the 1-(pyridin-4-yl)-ethylene-1,2-dithiolate were prepared and isolated as [PPh 4] +, [ n-Bu 4N] + 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 MS 4 core. The C–C and C–S bond lengths are consistent with ene-1,2-dithiolate form of the ligand and M III oxidation state. The Ni complexes are paramagnetic with an effective magnetic moment of ∼1.7 BM.