Synthesis and Characterization of Dinuclear Metal Complexes Stabilized by Tetradentate Schiff Base Ligands

Problem statement: The synthesis, spectroscopic properties and theoretical calculations of acetylacetonimine and acetylacetanilidimine Schiff-base ligands, L₁H and L₂H, respectively and their dinuclear complexes of the type [M₂L_nCl₂(H₂O)₂], where n = 1 or 2, M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) are described. Approach: The new tetradentate dianion Schiff base ligand which was used as stabilizers for the complexes were prepared by condensation of hydrazine with acetylacetone or acetylacetanilide. The dinuclear complexes of theses ligands were synthesized by treating an ethanolic solution of the prepared ligand with hydrated metal salts in molar ratio of 1:2 (L:M). Results: The ligand and their dinuclear metal complexes were characterized by CHN elemental analysis, FT-IR, UV-Vis, ¹HNMR (for the ligands), conductivity, magnetic susceptibility and theoretical calculation by using MM2 modeling program. Conclusion: The reaction of these ligands in a 1:2 (L:M) afford dinuclear M(II) metal complexes with tetrahedral arrangement around Co(II), Zn(II) and Cd(II) and square planar around Ni(II) and Cu(II).