Thermochemical parameters of dialkyldithiocarbamate chelates of indium(III)

Abstract

A series of dialkyldithiocarbamate chelates of indium(III) of the general formula In(S 2CNR 2) 3, (R = C 2H 5, n-C 3H 7, i-C 3H 7, n-C 4H 9 and i-C 4H 9), were prepared from the reaction of hydrochloric acid solution of metallic indium and the corresponding dialkylammonium salt of the ligand at pH = 3–4, giving yields better than 78%. The standard molar enthalpies of formation of crystalline dialkyldithiocarbamate chelates of In(III), were determined through reaction-solution calorimetry in acetone, at 298.15 K. The corresponding standard molar enthalpies of sublimation were estimated by means of differential scanning calorimetry. By combining of the values from these enthalpies, the standard molar enthalpies of formation in the gas were obtained. From the standard molar enthalpies of formation of the gaseous chelates the homolytic 191.9 ± 3.6, 167.9 ± 3.1, 136.4 ± 2.5, 174.3 ± 3.0 and 189.1 ± 3.9 kJ mol −1, and heterolytic 938.1 ± 3.6, 961.9 ± 3.1, 993.5 ± 2.7, 1003.0 ± 3.0 and 1047.3 ± 3.9 kJ mol −1, mean indium–sulphur bond-dissociation enthalpies were calculated.