Electronic and thermodynamic study of Indium (III) complex with N-ethyl-sulfonyldithiocarbimate

Abstract

Dithiocarbimate complexes are commonly utilized in research as vulcanization accelerators in the curing of rubber. This work describes the synthesis and thermodynamic study of an Indium (III) complex containing N-ethyl-sulfonyldithiocarbimate as ligand. The ligand degradation was investigated in water via electronic absorption spectroscopy in water. In addition, X-ray diffraction allowed us to identify the structure of the degradation product. The electronic absorption spectroscopy was also used to identify the absorption band related to the coordination process. Formation of the complex was analysed by isothermal titration calorimetry, which not only suggested a 1:2 metal to ligand stoichiometry, but also identified the thermodynamic parameters for the coordination process. These data demonstrated a favourable enthalpic variation (ΔHo < 0) for both sites and a positive entropic variation (TΔSo > 0) for the second site, corroborating the geometry change during the titration process. This was further investigated by DFT calculations regarding the structure and stability of ligand and complex formation complementing the overall conclusions of the experimental data by geometry, electronic transitions and vibrational analysis of the system.