The Cycle Destruction during Complex Formation of 4-salicylideneamino-3-hydrazino-5-mercapto-1,2,4-triazole with Ni (II) ions

Using single crystal X-ray diffraction method, it was shown that the interaction of 4-salicylideneamino-3-hydrazino-5-mercapto-1,2,4-triazole with Ni (II) acetate yields a complex of nickel with salicylidene-thiosemicarbazone instead of the expected complex with the corresponding Schiff base. A possible mechanism of hydrolysis of the thiotriazole ring is proposed. The N- (salicylidene) thiosemicarbazone is a tridentate and almost flat structure ligand coordinates to the nickel (II) cation through thiosemicarbazone sulphur, phenolic oxygen, and azomethine nitrogen atoms. The nickel (II) ion in the complex is four-coordinated in distorted square-planar geometry. The intermolecular hydrogen bonds N-H center dot center dot center dot N, as well as hydrogen bonds N-H center dot center dot center dot O, O-H center dot center dot center dot O and O-H center dot center dot center dot S through the solvate water molecules, give rise to the 3-D network of the complex [Ni(TSC)((NH2)(2)CS)]center dot H2O.