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.