A new macrocyclic Schiff base ligand, L, was synthesized by condensation reaction of 1,4-bis(2- formylphenyl)homopiperazine and 1,4-diaminobutane in acetonitrile. The Schiff base ligand was characterized by using elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic techniques. The metal (II) complexes [ML], were synthesized from the reaction of MCl2.nH2O (M: Co, Ni, Cu and Zn) with Schiff base ligand, L and characterized by elemental analyses and FT-IR. X-ray crystal structure of [CoLCl]þ distorted square pyramidal geometry with an N4Cl core, arising from coordination by the four donor nitrogen atoms from the macrocyclic framework and one Cl atom. It crystallizes triclinic space group, P-1 with a ¼ 7.1777(1) Å, b ¼ 11.0357 (2) Å, c ¼ 15.1520(2) Å, V ¼ 1183.14(3), Z ¼ 2, Dc ¼ 1.556 g cm3, m (MoKa) ¼ 0.156 mm1. Also, the bonding situation between the [MCl]þ and Ligand (L) fragments in [MLCl]ClO4 (M ¼ Co(II), Ni(II), Cu(II), Zn(II)) complexes were carried out by energy-decomposition analysis (EDA). The results showed that there is an increasing trend in the case of DEelstat of the complexes by changing the M from Co(II) to Zn(II).
