Crystal structures, spectroscopic, electrochemical, and antibacterial properties of a series of new copper(II) Schiff base complexes

<div><p>Two new and two previously reported Schiff base ligands as well as four corresponding new Cu(II) complexes (CuL^1–4) were synthesized and characterized. The Schiff base ligands were synthesized from condensation of 5-bromo-2-hydroxy-3-nitrobenzaldehyde with aliphatic (H₂L^1–2) or aromatic (H₂L^3–4) diamines. Crystal structures of CuL² and CuL³ were determined by X-ray crystallography. Antibacterial properties of these ligands and complexes were studied against four human pathogenic bacteria. The complexes showed moderate antibacterial activities, higher than those of the ligands.</p>