Journal article Open Access
Lalisa Wakjira Duresa
This paper focuses on synthesis and characterization of ligands and complexes. The ligands, 3-(2-hydroxyphenyl)-2-imino-1-thiazolidin-4-one (C9H8O2N2S) and 3-(2-hydroxyphenyl)-2-imino-1-oxazolidin-4-one (C9H8O3N), synthesized by cyclocondensation of 2-chloro-N-(2-hydroxyphenyl) acetamide, obtained by reaction of o-aminophenol with chloroacetylchloride, with potassium thiocyanate and potassium cyanate respectively. The metal complexes were prepared by refluxing solutions containing each ligand and metal salt in hot ethanol in 1:1 molar ratio. Analyses and conductometric results revealed 1:2 metal-ligand ratio and nonelectrolytic nature of the complexes respectively. IR spectral data revealed that both heterocyclic ligands coordinate through their heterocyclic nitrogen and phenolic oxygen to the metal and act as anionic bidentate ligands. Magnetic susceptiblity studies indicated square planar geometry of [NiL2].2H2O complex whereas other complex exhibiting magnetic moments less than spin-free d8 geometry seemed to be equilibrium mixture of four coordinate tetrahedral and square planar geometries owing to high spin to low spin or vice versa spin crossover phenomenon. However, splitting patterns of d-d bands in the electronic spectra of the complexes in solutions are consistent with their square planar geometry; tetrahedral stereochemistry has most probably been changed to square planar form by interaction with the solvent molecules. Newly synthesized complexes of Ni(II) which were 1:2 metal-ligand ratio were nonelectrolytic and formed by coordination of the ligands through their heterocyclic atoms and phenolic oxygen.