Complexes of a triazine-3-thione ligand with divalent metals crystal structure of [CdL2DMF]2•2DMF•1/4H2O

The synthesis and characterization of Cd(II), Zn(II), Pb(II), Co(III) and Ni(II) complexes of 5-methoxy-5,6-diphenyl-4,5-dihydro-2H-[1,2,4]triazine-3-thione LH2OCH3 are reported. The stoichiometry of the complexes was found to be 1:2 except for cobalt complex 4 where the ratio is 1:3. In all complexes the triazine is deprotonated and acts at least as a NS bidentate ligand. The complexes have been characterised by microanalysis, mass spectrometry, I, R, multinuclear (H-1, C-13 and Cd-113) NMR, C-13 CP/MAS NMR and magnetic susceptibility. In addition, the structure of the complex [Cd(DMF)L-2](2) center dot 2DMF center dot 1/4H(2)O (1a), has been determined by X-ray diffraction. Crystallographic data show that the complex consists of a dinuclear structure, in which the ligands act as bidentate NS donors and with two of the four ligands acting as a bridge between the metal ions via the sulfur atom. According to the spectroscopic data, the same disposition is proposed for complexes 2, and 3. Complex 4 is an low spin octahedral monomeric structure with the ligand acting as a bidentate NS donor and where the metal has been, oxidised to Co(III). In complex 5 the Ni(II) ion is in a square planar N2S2 disposition, formed by two ligands. The redox behaviour of the cadmium and cobalt complexes was explored by cyclic voltammetry and shows metal-centred processes. (c) 2005 Elsevier Ltd. All rights reserved.