DNA binding studies and antibacterial properties of a new Schiff base ligand containing homopiperazine and products of its reaction with Zn(II), Cu(II) and Co(II) metal ions: X-ray crystal structure of Cu(II) and Zn(II) complexes

Abstract

In this paper, a new symmetrical, potentially hexadentate N4O2, macroacyclic Schiff base ligand (H2L) was derived from the condensation of a polyamine, 2,2′-((1,4-diazepane-1,4-diyl)bis(methylene))dianiline (A), with 2-hydroxybenzaldehyde. Three Schiff base complexes were prepared by direct reaction of H2L with Cu(II), Zn(II) and Co(II) ions in equimolar ratios. For Co(II), the metal was oxidized to Co(III), forming the six-coordinate complex with the desired Schiff base ligand [CoL]ClO4, however with Cu(II) and Zn(II) ions, the hydrolysis of the ligand occurred with the loss of one benzaldehyde group, resulting in the formation of the five-coordinate mono Schiff base ligand (HL′), with a N4..