Evaluation of the anion effect on the structure and biological properties of Co(II) complexes with a chalcone‐type ligand

Abstract In the current work, four Co(II) complexes of the chalcone ligand with the IUPAC name 3‐(4‐chlorophenyl)‐1‐(pyridin‐2‐yl)prop‐2‐en‐1‐one were synthesized to evaluate the role of the incorporated anion on the structure and characteristics of the prepared complexes. Based on the spectral FTIR, mass, UV–vis tools, TGA/DTA, magnetic moment in addition to C, H, N analysis, the prepared complexes assured to have the empirical formulas [CoL(OAc) 2 ]•1.5EtOH, [CoL(NO 3 ) 2 ]•0.5EtOH, [CoL(SO 4 )]•0.5EtOH, and [CoL(ClO 4 ) 2 ]•1.5H 2 O, where L is the chalcone ligand. In all complexes, the ligand chelates to the central Co ions by the oxygen and nitrogen atoms of carbonyl and azomethine groups, successively, as confirmed by the spectra of IR. Tetra‐coordination forming tetrahedral structures are concluded for all complexes by the results of UV–vis spectra and magnetic moment. Antimicrobial investigation has been conducted against a broad range of microorganisms, affording the enhanced activity of the complexes over the free ligand. The most active complex is L‐Co‐OAc whereas the least active complex is L‐Co‐ClO 4 , especially against Pseudomonas aeruginosa . Furthermore, the in silico molecular docking studies of the ligand and cobalt chelates on Pseudomonas aeruginosa (PDB: 2UV0) active site indicated the strong interactions and hence supports the excellent biological response against the bacterium.