Synthesis and spectral properties of cobalt(III) complexes containing SCN dimethylglyoxime and heterocyclic N-donor ligands

Different nitrogen donor ligands (pyridine, piperidine, quinoline, iso-quinoline, triazole, indole, benzimidazole, benzotriazole, carbazole) react with CO(SCN)(2) and dimethylglyoxime (DH2) in ethanolic medium in presence of air to form a number of new Co(III) complexes of the type trans[Co(DH)(2)(L)(SCN)], which are characterised on the basis of electronic and IR spectra NMR, (H-1 and C-13) spectra, thermogravimetric (TG-DT) analysis and conductance measurements. The thiocyanate group is S-bonded. The NMR observation suggests that in solution, these compounds exist as mixtures of neutral species [Co(DH)(2)(L)(SCN)] and the salt [Co(DH)(2)(SCN)(2)]. TG and DT analysis show that these complexes proceed through polymeric intermediate, and give Co3O4 as the end product.