IRON(II) AND NICKEL(II) COMPLEXES OF 2,6-DI(THIAZOL-2-YL)PYRIDINE AND RELATED LIGANDS

2,6-Di(thiazol-2-yl)pyridine (1a), 2,6-di(4-methylthiazol-2-yl)pyridine (1b) and 2,6-di(2-imidazolin-2-yl)pyridine (3) have been prepared by the reaction of pyridine-2,6-dicarbothioamide with bromoacetaldehyde diethyl acetal, bromoacetone and ethylenediamine, severally. Bis(ligand) iron(II) and nickel(II) complexes of all ligands have been prepared. The bis(ligand) iron(II) complexes of (1a) and (3) are low-spin whereas that of (1b) is high-spin at room temperature and undergoes a thermally induced spin transition. The field strengths of the ligands, determined from the spectra of their nickel(II) complexes, correlate well with the observed magnetic behaviour of their iron(II) complexes. The field strengths of (1a) and (1b) are found to be marginally less than those of the isomeric ligands 2,6-di(thiazol-4-yl)pyridine (2a) and 2,6-di(2-methylthiazol-4-yl)pyridine (2b).