Synthesis, Characterization and Applications of the Synthesized Copper(II) Complexes Containing Schiff Base Ligands in Antimicrobial Activities and Catalytic Reduction of Nitroaromatic Compound

This articles describes the preparations of a series of Schiff base ligands [L1], [L2], and [L3] and their corresponding copper(II) complexes; [C1], [C2] and [C3]. The synthesized ligands and their copper(II) complexes were characterized using Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-Vis) spectroscopy. The ability of the compounds to inhibit bacteria species were tested against E. Coli, Staphyllococcus and Streptococcus bacterial. The results revealed that all the compounds were active against bacteria species. The inhibition rate is in order L3>L2>L1 for ligands and C3>C2>C1 for complexes. The catalytic activities of the synthesized copper(II) complexes were evaluated in the reduction of aromatic compounds in the presence of sodium borohydride which acts as reducing agent. The progress of reaction was monitored using UV-visible spectroscopy and the percentage conversion was determined from the spectroscopy data. The results showed that [C3] has the highest catalytic activities with 97.5% conversion, followed by [C2] complex with 95.2% conversion, then [C1] complex with 90.8% conversion. The optimization of the catalyst dose shows that 1.0 mg of the catalyst dose was the most optimized amount with the highest conversion of 94.6% than other dose of 0.5 mg (92.4%) and 1.5 mg (91.4%). Recyclability and reproducibility tests of copper(II) complexes confirmed that all the three complexes were active, efficient and possess excellent reproducibility with consistent catalytic performances and could be re-used again without significant decrease in the catalytic activities.