THERMAL DECOMPOSITION OF TRIS(PIPERIDYLDITHIO- CARBAMATES) OF As(Ill), Sb(lll) AND Bi(lll)

Thermal studies by TG, DTG and DTA of tris(piperidyldithiocarbamates) of arsenic(l I I), antimony(Ill) and bismuth(Ill) of the general type M[S2CN(CH2)5] 3 (M = As, Sb and Bi) have been carried out in nitrogen and air, as well as under vacuum, to determine their modes of decomposition. The apparent activation energies were determined by graphical methods and the TIN temperatures were calculated from the TG profiles. A possible mechanism of the decomposition reaction is suggested on the basis of the results of their pyrolysis and their mass spectral data. The intermediates obtained at the end of various decomposition steps were identified via their elemental analysis, i.r. spectral data and X-ray diffraction studies. A dimeric structure of type M2[S2CN(CH2)5] 4 (M -- As, Sb) is proposed. As part of a research project which started several years ago in our laboratory, a large number of dithiocarbamato complexes with various metals have been synthesized, and their structures and chemistry have been studied extensively. In the knowledge of their applications and importance in industry, it was of interest to carry out thermal studies on these complexes. Hitherto, several papers have appeared concerning the thermal behaviour of transition metal dithiocarbamato complexes. However, the thermal studies on the dithiocarbamato complexes of As(Ill), Sb(lll) and Bi(lll) are limited to only three papers. A brief review of these is given below, highlighting the points connected with our