Thermal decomposition of trialkyl/arylphosphine gold(I) cyanide complexes

Combined TG/DTA techniques have been used to study the thermal decompositio n of R3PAuCN (where R is ethyl, cyclohexyl, o-tolyl, m-tolyl, p-tolyl, ally l, cyanoethyl, 1-naphthyl and phenyl) complexes. It was observed that all o f these complexes underwant decomposition cum redox reactions in the range of 200-600 degrees C with evolution of both trans ligands, which are phosph ine and cyanide, leaving metallic gold as a residue. The thermal decomposit ion of o-Tol(3)PAuCN has revealed that this is a stepwise process. In the f irst step decomposition takes place with evolution of phosphine and generat ion of AuCN, which in second step undergoes a redox reaction to produce met allic gold. The DTA curves have also confirmed these results.