Synthesis, Properties and Spectroscopic Studies of Cobalt (II) and Cobalt (III) Complexes with Planar Dithioxamides

The complexes [Coiii(LH2)3]X3 (LH2 = dithiooxamide, N-methyldithiooxamide, N,N'-dimethyldithiooxamide; X = Cl, Br, l) and [CoiiL]n have been prepared. They were characterized by analyses, thermal techniques, magnetic susceptibilities and spectroscopic (ligand-field, 13C-NMR, FT-IR) methods. The vibrational analysis of the prepared complexes is given using NH/ND and CH3/CD3 isotopic substitutions. The neutral dithiooxamides exhibit a bidentate chelating S,S-coordination, while the doubly deprotonated dithiooxamido anions act as bis-bidentate bridging S,N/N,S-ligands giving trans polymeric structures. The Co(III) complexes are octahedral with CoIIIS6 coordination spheres. A square planar geometry around Co(II) is assigned for the polymeric compounds.