Electrochemical synthesis and structural characterisation of zinc, cadmium and mercury complexes of heterocyclic bidentate ligands (N, S)

The electrochemical oxidation of anodic metal (zinc or cadmium) in acetonitrile solutions of 3trifluoromethylpyridine-2-thione (3-CF3-pySH) or 5-trifluoromethylpyridine-2-thione (5-CF3-pySH) affords complexes [M(R-pyS)2], M = Zn, Cd, R = 3-CF3, 5-CF3. Adducts of these compounds with 2,2-bipyridine (bipy) or 1,10-phenanthroline (phen) were also obtained when the bidentate coligand was present in the cell. On the other hand, reaction of a methanol solution of mercury acetate with the corresponding pyridine-2-thione in the presence of triethylamine affords compounds of composition [Hg(R-pyS)2]. All the compounds obtained have been characterised by microanalysis, IR spectroscopy and, in cases where the compound was sufficiently soluble, by 1H, 13C and 199Hg NMR spectroscopy. The compounds [Zn(3-CF3-pyS)2(bipy)](1), [Zn(3-CF3-pyS)2 (phen)]·CH3CN (2), [Zn(5-CF3-pyS)2(bipy)](3), [Cd(3-CF3-pyS)2(DMF)]2(4), [Cd2(5-CF3-pyS)4(DMF)]n(5), [Cd(3CF3-pyS)2(bipy)]·CH3CN (6), [Hg(3-CF3-pyS)2](7) and [Hg(5-CF3-pyS)2](8) were also characterised by X-ray diffraction.