Complexes of a triazine-3-thione ligand with divalent metals: Crystal structure of [CdL 2DMF] 2 · 2DMF · 1/4H 2O

Abstract

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 LH 2OCH 3 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, IR, multinuclear ( 1H, 13C and 113Cd) NMR, 13C CP/MAS NMR and magnetic susceptibility. In addition, the structure of the complex [Cd(DMF)L 2] 2 · 2DMF · 1/4H 2O ( 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 N 2S 2 disposition, formed by two ligands. The redox behaviour of the cadmium and cobalt complexes was explored by cyclic voltammetry and shows metal-centred processes.