The Different Effects of Metal Ions on the Synthesis of Macroacyclic Compounds: X-ray Crystal Structure, Theoretical Studies, Antibacterial and Antifungal Activities

Abstract

In this work, we have been involved studying the synthesis of some new macroacyclic complexesI-VIII, so we tried to get propoesed results in all cases but in the case of compound I, according to X-ray crystal structure, the product is a protonated Schiff base. By the reaction of a 1 : 1 (metal : ligand) stoichiometry of two known Schiff base ligands, 1,2-bis(2-((2-hydroxy ethylimino)methyl)phenoxy)ethane (H2L1) or 1,3-bis(2-((2-hydroxyethylimino)methyl) phenoxy)propane (H2L2) and appropriate metal salts in methanol in the case of Ni2+, Cu2+ and Co2+, macroacyclic complexes were prepared. When using Mn2+ only protonated Schiff base ligands is the final product. All compounds were characterized by microanalysis and IR spectroscopy, whereas compound I was also characterized by single crystal X-ray. The X-ray structure of compound I showed that both protonated imines are neutralized by two perchlorate ions. Computational calculations of relevant complexes are done by using one of the hybrid density functional theories which are a B3LYP method with 6-31G(d) basis set in a vacuum. Also, the synthesized compounds were screened for their antibacterial activities against nine bacterial strains and showed antibacterial effects. These complexes also showed antifungal effects on two species of Candida.