Bidentate ligands and their Cu(II) complexes: Structural characterization, electrochemical properties and biological evaluation

In this manuscript, three bidentate ligands 2-[(2-methoxybenzylidene)amino]phenol (HA(1)), 2-[(3,4,5-trimethoxybenzylidene) amino]phenol (HA(2)) and 2-[(2,3,4-trimethoxybenzylidene) amino]phenol (HA(3)) were synthesized from the reaction of the 2-aminophenol and methoxy benzaldehyde derivatives in MeOH solution. The Cu2+ metal complexes of these ligands were obtained in the 1:1 (M:L) ratio. All the compounds were characterized by the micro analytical and spectroscopic techniques. The single crystals of the bidentate ligands (HA(2) and HA(3)) were obtained from the recrystallization from the MeOH solution and their structural characterizations were conducted by the X-ray diffraction method. Antimicrobial activity studies of the bidentate ligands and their Cu2+ metal complexes were tested towards S. aureus, E. coli, B. cereus, B. subtilis, S. typhimurium as bacteria and C. albicans as fungi and the complex Cu2+ of the ligand HA(2) showed the highest activity against to the S. aureus. While the ligands HA(2) and HA(3) do not show the activity against the bacteria and fungi, the ligand HA(1) has the activity against to the S. typhimurium, S. aureus and C. albicans. Electrochemical behaviours of all compounds have been investigated in DMF solution and it was found that the cathodic and anodic values of the [CuA(3)(CI)H2O] complex shifted to the more positive regions owing to the positions of the methoxy groups on the benzaldehyde ring. (C) 2019 Elsevier B.V. All rights reserved.