AUTHOR=Gatto Claudia C. , Dias Lucas M. , Paiva Clarisse A. , da Silva Izabel C. R. , Freire Daniel O. , Tormena Renata P. I. , Nascimento Érica C. M. , Martins João B. L. 

TITLE=Effects of changing ions on the crystal design, non-covalent interactions, antimicrobial activity, and molecular docking of Cu(II) complexes with a pyridoxal-hydrazone ligand

JOURNAL=Frontiers in Chemistry

VOLUME=12

YEAR=2024

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2024.1347370

DOI=10.3389/fchem.2024.1347370

ISSN=2296-2646

ABSTRACT=<p>The present work reports the influence of the presence of different ions (Cl<sup>−</sup>, Br<sup>−</sup>, NO<sub>3</sub><sup>−</sup>, or SO<sub>4</sub><sup>2−</sup>) on the formation and proprieties of Cu(II) complexes with pyridoxal-benzoylhydrazone (PLBHZ). Four new complexes were successfully synthesized, [CuCl<sub>2</sub>(PLBHZ)] (1), [CuBr<sub>2</sub>(PLBHZ)] (2), [CuCl(PLBHZ)H<sub>2</sub>O]⋅NO<sub>3</sub>⋅H<sub>2</sub>O (3), and [CuSO<sub>4</sub>(PLBHZ)H<sub>2</sub>O]⋅3H<sub>2</sub>O (4), and characterized by spectroscopic and physicochemical methods. A single-crystal X-ray study reveals the Schiff base coordinated to the metal center tridentate by the <italic>ONS</italic>-donor system, resulting in distorted square pyramidal coordination geometries. Noncovalent interactions were investigated by 3D Hirshfeld surface analysis by the <italic>d</italic><sub><italic>norm</italic></sub> function, 2D fingerprint plots, and full interaction maps. The ion exchange is important in forming three-dimensional networks with π⋅⋅⋅π stacking interactions and intermolecular hydrogen bonds. The <italic>in vitro</italic> biological activity of the free ligand and metal complexes was evaluated against Gram-positive and Gram-negative bacterial strains and the free pyridoxal-hydrazone ligand showed higher activity than their Cu(II) complexes. Molecular docking was used to predict the inhibitory activity of the ligand and complexes against Gram-positive <italic>Staphylococcus aureus</italic> and Gram-negative <italic>Escherichia coli</italic> bacteria.</p>