Coordination compounds of hydrazine derivatives with transition metals, Part 17. Nickel (II) and cobalt(II) chelates with pyridine-2-aldehyde semi- and thiosemicarbazone

Abstract

The chelation abilities of both pyridine-2-aldehyde semicarbazone (Pysc) and thiosemicarbazone (Pytsc) towards NiII and CoII salts have been investigated. A series of pentacoordinate monoligand chelates: Ni(Pysc)X2, Ni(Pytsc)X2 and Co(Pysc)X2 and octahedral bis ligand chelates Ni(Pysc)2X · NO3 Ni(Pytsc)2X2 and Co(Pysc)2X2 have been isolated and identified. In these chelates, both Pysc and Pytsc act as neutral tridentate ligands. The deprotonated form of Pyts, which arises through enolization, is identified in NII chelates and is of the type Ni(PytscH)2 and Ni(PytscH)X. Spectral and magnetic measurements are presented and attention is drawn to the effect of temperature on the solution spectra of some of the chelates.