Complexes of tetradentate Schiff base ligands with divalent transition metals

New homo-dinuclear metal complexes of the Schiff base ligands 2-{4-[4-(2-hydroxyphenyliminomethyl)anilinomethyl]-phenyliminomethyl} phenol (H2L1), 3-{4-[4-(2,3-di-hydroxy-phenyliminomethyl)anilinomethyl]phenyliminomethyl}- 1,2-benzene-diol (H2L2) and 4-bromo-2-{4-[4-(5-bromo-2-hydroxyphenyliminomethyl)anilinomethyl]phenyliminometh-y1}phenol (H2L3) have been prepared in EtOH solution and 2 were characterized by infrared, electronic and H-1 and C-13 NMR spectra, and by magnetic susceptibilities and molar conductivity measurements. The mass spectra of the Schiff base ligands were recorded. The ligands coordinate as neutral ligands via the Schiff base azomethine nitrogen and phenolic oxygen atoms. The keto-enol tautomeric forms of the Schiff base ligands H2L1, H2L2 and H2L3 have been investigated in polar and apolar organic solvents.