Since the appearance of the term palladacycle, as coined by Trofimenko^[1], one of the most salient group of such compounds is the thiosemicarbazone class.

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; after which there were conveniently treated with a palladium salt thus yielding the corresponding palladacycle. All show a tetranuclear structure with [C, N, S] coordination of the ligands to the metal centers.

[1] S. Trofimenko, Inorg. Chem., 1973, 12, 1215.