Thermochemical parameters of dialkyldithiocarbamate chelates of indium(III)

A series of dialkyldithiocarbamate chelates of indium(III) of the general f ormula In(S2CNR2)(3), (R = C2H5, n-C3H7, i-C3H7, n-C4H9 and i-C4H9), were p repared from the reaction of hydrochloric acid solution of metallic indium and the corresponding dialkylammonium salt of the ligand at pH = 3-4, givin g yields better than 78%. The standard molar enthalpies of formation of cry stalline dialkyldithiocarbamate chelates of In(III), were determined throug h reaction-solution calorimetry in acetone, at 298.15 K. The corresponding standard molar enthalpies of sublimation were estimated by means of differe ntial scanning calorimetry. By combining of the values from these enthalpie s, the standard molar enthalpies of formation in the gas were obtained. Fro m the standard molar enthalpies of formation of the gaseous chelates the ho molytic 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 b ond-dissociation enthalpies were calculated. (C) 2000 Elsevier Science B.V. All rights reserved.