Synthesis and spectral characterization of zinc(II) complexes of N(4)-substituted thiosemicarbazone derived from salicylaldehyde: Structural study of a novel -OH free Zn(II) complex

Five novel zinc(II) complexes of salicylaldehyde 3-hexamethyleneiminyl thiosemicarbazone were synthesized and physico-chemically characterized. The complexes were given the formulae [Zn(HL)2] (1), [Zn(L)py] (2), [Zn(L)bipy] · 3.5H2O (3), [Zn(L)phen] · H2O (4) and [Zn(L)γ-pic] (5). The thiosemicarbazone binds the metal as a dianionic ONS donor ligand in all the complexes, except in 1. Compound 1 is a homoleptic complex with zinc occupying the center of a distorted tetrahedral environment and being coordinated by two azomethine nitrogen and two thiolate sulfur atoms.