N, N′-Dialkyldithiocarbamate chelates of indium(III): alternative synthetic routes and thermodynamics characterization

Abstract

Alternative synthetic routes to prepare N, N′-dialkyldithiocarbamate complexes of indium(III), In(S 2CNR 2) 3 (R = CH 3, C 2H 5, n-C 3H 7, i-C 3H 7, n-C 4H 9 and i-C 4H 9) from the metallic element and from indium monohalides, InX(X = Cl, Br and I) were established. The proposed mechanism of reaction involving InX considering a ligand redistribution reaction of XIn(S 2C–NR 2) 2 initially produced, which could be derived from the insertion of InX into sulfur–sulfur bond of the tetralkylthiuram disulfide. The thermal decomposition of the In(S 2CNR 2) 3 (R = CH 3, C 2H 5, n-C 3H 7, i-C 3H 7, n-C 4H 9 and i-C 4H 9) compounds was investigated by the thermogravimetric technique, where two pathways were detected, depending on the dialkyldithiocarbamato ligand. The first step leads to indium metal, or alternatively In 2S 3, as the final residue for R = C 2H 5, n-C 3H 7, i-C 4H 9 and for R = CH 3, i-C 3H 7, n-C 4H 9, respectively. The corresponding standard molar enthalpies of sublimation of all compounds were determined by means of differential scanning calorimetry and methods of estimation.