AROMATIC DIIMINE DEPENDENT STRUCTURAL FEATURES OF IRON(II), COBALT(II) AND NICKEL(II) COMPLEXES WITH SOME TETRADENTATE SCHIFF-BASE LIGANDS

Complexes of iron(II), cobalt(II) and nickel(II) with four tetradentat e (ONNO) Schiff base ligands viz salicylaldehyde-o-phenylenediimine (S alophen) salicylaldehyde metaphenylenediimine (Salmphen), 2-hydroxy-1- napthaldehyde o-phenylenediimine (Nalophen) and 2-hydroxy-1-naphthalde hyde m-phenylenediimine (Nalmphen) are shown to have aromatic diimine dependent structural features. Although, Salophen complexes are known, complexes of Fe(II), Co(II) and Ni(II) with Salmphen. Nalophen Schiff base ligands are prepared and characterised by various physicochemica l and spectral studies. While Salophen and Nalophen give monomeric and low-spin complexes the ligands prepared using metaphenylenediamine fo rm binuclear complexes presumably due to longer chain length and less steric strain present in the latter ligands. The structural characteri sation of a group of complexes are presented. In addition, organocobal t complexes of Salophen and Nalophen are prepared and characterised.