Synthesis and characterization of N4O2 macroacyclic Schiff-base ligand contaning piperazine moiety and its mononuclear Zn (II) complex

The polyamine 2,2 -(piperazine-1,4-diylbis(methylene))dianiline (A) was synthesized by the reaction of piperazine with 2-nitrobenzaldehyde. IR spectrum of polyamine Aexhibit a (NH2) vibration in 3347-3447 cm-1. In the mass spectrum of polyamine A, presence of the peak at 296 m/z confirms the synthesis of polyamine. Macroacyclic Schiff-base ligand H2L with the N4O2 donor system was synthesized from condensation of 2-hydroxybenzaldehyde with polyamine A. IR spectrum of ligand exhibited a (C=N)vibration in 1616 cm-1. In the mass spectrum of ligand (H2L) presence of a peak at 504 m/z confirms the synthesis of ligand. The elimination of C=O and NH2 band in IR spectrum of ligand shows the ligand synthesis. The corresponding complex was synthesized from direct reaction of zinc (II) metal ion and ligand (H2L) in the methanol solvent (Scheme 1). In the IR spectrum of the complex, (C=N) in the 1613 cm-1, and also in mass spectrum of complex the presence of peak at 568 m/z confirms the synthesis of complex. The elemental analysis and 1H and 13C NMR confirm the synthesis of all compounds [1-2].