Synthesis, characterization, and antibacterial activity of two zinc(II) complexes with Schiff bases from halogenated salicylaldehyde and amantadine

Abstract

By a condensation reaction of halogenated salicylaldehyde and amantadine, two new Schiff base ligands (HL1 and HL2) were synthesized, respectively. A followed mixture of the ligands and zinc(II) chloride in the presence of NaOH in an alcoholic medium brought out two novel complexes (ZnL 2 1 ) (I) and (ZnL 2 2 (II). These two complexes were characterized by the means of melting point, elemental analysis, IR, UV-Vis, 1H NMR, molar conductance and single-crystal X-ray diffraction analysis. X-ray diffraction analysis reveals that I crystallizes in monoclinic system, P21/c space group, a = 9.7812(5), b = 25.6198(12), c = 27.7381(18) Å, β = 105.881(4), F(000) = 1416, R 1 = 0.0731, wR 2 = 0.1147; II crystallizes in orthorhombic system, Pbca space group, a = 11.1717(10), b = 20.5888(15), c = 27.7381(18) Å, F(000) = 2976, R 1 = 0.1341, wR 2 = 0.1410. Both in I and II, the central zinc(II) atom is four-coordinated via two nitrogen atoms and two oxygen atoms from the corresponding Schiff base ligands, forming a distorted tetrahedral geometry.