Abstract
Three new bis-azomethine derivatives were synthesized in a good yield, along with their copper(II) complexes and confirmed by IR, C-13-NMR, H-1-NMR, MS, ESR, powder XRD and UV-vis spectroscopy. The spectral studies indicated that the ligands in all complexes act as dibasic tetradentate, coordinated through two azomethine nitrogen and two deprotonated phenolic oxygen atoms. Square planar geometries were assigned for Cu(II) complexes in monomeric structures. Also, quantum chemical calculations using DFT were conducted to elucidate the effect of quantum chemical parameters on the molecular and electronic structures of the molecules under consideration, and then confirming their electrochemical behavior and biological effectiveness. There were good correlations between practical and theoretical studies. The redox pathway of bis-azomethine derivatives and their Cu(II) complexes was elucidated and confirmed based on experimental and theoretical calculations. In vitro antimicrobial effectiveness of the synthesized three ligands and their Cu(II) complexes exhibited varying degrees of inhibitory effect on the growth of the test pathogenic microorganisms, confirming that antimicrobial efficiency is dependent on the molecular structure of the prepared compounds and their liposolubility. The MIC was also determined for the compound H2Lc which exhibited the highest antimicrobial activity against each of Pseudomonas aeruginosa (G-) and Candida albicans.