DFT analysis, spectroscopic study and biological activity of a newly synthesized benzoylhydrazone binuclear Cu(II) complex

• Published in: Journal of inorganic biochemistry 2020-03, Vol.204, p.110949, Article 110949
• Main Authors: Santiago, Pedro H.O., Tiago, Fernanda S., Castro, Mariana S., Souza, Paulo E.N., Martins, João B.L., Gatto, Claudia C.
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; Antimicrobial activity; Bacteria - drug effects; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Copper - chemistry; Crystal structure, density functional theory; Cu(II) complex; Fungi - drug effects; Hydrazones - chemistry; Models, Molecular; Quantum Theory; Spectroscopy, Fourier Transform Infrared
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2019.110949

The current work reports a joint experimental and theoretical study of a novel Cu(II) complex [CuL(μ-CH3COO)]2, based on 2-acetylpyridine-benzoylhydrazone ligand (HL). The two Cu(II) atoms are five-coordinated, consisting of three NNO-donor atoms from the hidrazone ligand connected by acetate bridges. In addition to the structural analysis, the complete characterization includes magnetic susceptibility, elemental analysis, FT-IR and UV–Vis. Two different approaches of Density Functional Theory (DFT) with localized basis set and plane waves were performed. The theoretical calculations were used to optimize the complex geometry of the new structure allowing a better understanding of its spectroscopic properties with insights of most important interactions. Thereunto, we made a comparison between the following functionals: B3LYP, PBE1PBE, B3PW91, ω-B97XD, M06 (hybrids), CAM-B3LYP (long range hybrid), and B97-d (pure), using localized basis set, and for plane waves we used the PW91 functional. Considering the expected antifungal and antibacterial activity of hydrazone derivative ligand, the antimicrobial activity of HL and the complex [CuL(μ-CH3COO)]2 was tested against pathogenic Gram-positive and Gram-negative bacteria and fungi. The synthesized new structure of hydrazone complexed with copper (II) shows antimicrobial activity, and magnetic susceptibility results indicate weak antiferromagnetic coupling between the copper atoms. Schematic representation of the synthesized new hydrazone copper (II) complex characterized using spectroscopy and density functional theory (DFT), following the evaluation of antibacterial and antifungal activities. [Display omitted] •Cu(II) complex studied by X-ray crystallography and density functional theory.•The binuclear Cu(II) complex has a distorted square pyramidal structure.•The antimicrobial activity was verified against pathogenic fungi and bacteria.•The periodic model results show accurate for geometry prediction.•Solvent model make possible a better view about the spectral measurements.