Synthesis and characterization of mixed-ligand complexes of nickel(II) with 5,5′-thiodisalicylic acid and amines

The 5,5′-thiodisalicylato complexes of nickel(II) with water, ammonia, methylamine and pyridine were synthesized and their structure established to be Ni(TDSA)L₂·nH₂O], where TDSA = 5,5′-thiodisalicylic acid, C₆H₃(OH)(COOH)SC₆H₃(OH)(COOH)]. LH₂O, NH₃ CH₃NH₂ or pyridine, and n=3 for H₂O, 2 for NH₃ and CH₃NH₃, and 1 for pyridine complexes, from elemental analysis, IR and electronic spectroscopy, and magnetic susceptibility measurement. The thermal behaviour of the complexes has been studied by TG and DTA. TG shows three main steps of decomposition, viz. dehydration, axial base liberation, and decarboxylation leading to the formation of NiO at the final stage.