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 [NiH2L](ClO4)2 (1), [CuH2L](ClO4)2 (2), [MnH2L](ClO4)2 (3) and [CdH2L](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 equemolar ratios. The ligand, H2L was synthesized by reaction of 1, 4- bis (2- formylphenyl) piperazine and ethanol amine and characterized with IR and 1H,13C NMR spectroscopy. All complexes were characterized by IR, Mass and elemental analysis. Also, theoretical studies on structures, molecular orbital and nature of bond in latter complexes were 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 H2L and metal ions in latter complexes are as following: [MnH2L]2+[NiH2L]2+<[CdH2L] 2+<[CuH2L]2+. Also the calculated total spin density for Mn2+, Ni2+ and Cu2+ metal ions are about 4.76, 1.49, and 0.45, respectively.