Synthesis and characterization of novel thiosemicarbazone palladacycles

Since the appearance of the term palladacycle, as coined by Trofimenko[1], one of the most salient groups is the one comprising thiosemicarbazones. Herein, the synthesis and characterization of several palladium cyclometallated compounds with thiosemicarbazone ligands is discussed. The ligands were synthesized by treatment of a ketone with four different thiosemicarbazides in acidified aqueous solution. Then, they were conveniently treated with a palladium salt to yield the corresponding palladacycle. All show a tetranuclear structure with [C, N, S] coordination of the ligands to the metal centers.