Synthesis, Characterization and Theoretical Studies of a New Macroacyclic Schiff- Base Ligand Containing Piperazine Moiety and Related Mn(II), Cu(II), Ni(II) and Cd(II) Complexes

Four new [MnL](ClO4)2 (1), [CuL](ClO4)2 (2), [NiL](ClO4)2 (3) and [CdL](ClO4)2 (4), complexes were prepared by the reaction of a new Schiff base ligand and Cu(II), Ni(II), Mn(II) and Zn(II) metal ions in equimolar ratios. The ligand, L was synthesized by the reaction of 1,4-bis(2-formylphenyl)piperazine and ethanolamine and characterized by IR and 1H, 13C NMR spectroscopies. All complexes were characterized by IR, EI-Mass and elemental analysis. Theoretical studies on structures, molecular orbital and nature of bond in these complexes were also carried out with NBO analysis at DFT (BP86) method using Def-2/SVP basis set. The results of WBI and charge transfer confirm that the covalent character in bonding interactions between the L and metal ions in [MnL]^2+ and [CuL]^2+ complexes is minimum and maximum, respectively.