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

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

doi:10.3389/fchem.2024.1347370

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

Front Chem. 2024 Feb 1:12:1347370. doi: 10.3389/fchem.2024.1347370. eCollection 2024.

Authors

Claudia C Gatto¹, Lucas M Dias¹, Clarisse A Paiva¹, Izabel C R da Silva², Daniel O Freire², Renata P I Tormena², Érica C M Nascimento³, João B L Martins³

Affiliations

¹ Laboratory of Inorganic Synthesis and Crystallography, Institute of Chemistry, University of Brasilia, Brasília-DF, Brazil.
² Graduate Program in Health Sciences and Technologies, Faculty UnB Ceilândia, University of Brasilia, Brasília-DF, Brazil.
³ Laboratory of Computational Chemistry, Institute of Chemistry, University of Brasilia, Brasília-DF, Brazil.

Abstract

The present work reports the influence of the presence of different ions (Cl^-, Br^-, NO₃ ^-, or SO₄ ^2-) on the formation and proprieties of Cu(II) complexes with pyridoxal-benzoylhydrazone (PLBHZ). Four new complexes were successfully synthesized, [CuCl₂(PLBHZ)] (1), [CuBr₂(PLBHZ)] (2), [CuCl(PLBHZ)H₂O]⋅NO₃⋅H₂O (3), and [CuSO₄(PLBHZ)H₂O]⋅3H₂O (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 ONS-donor system, resulting in distorted square pyramidal coordination geometries. Noncovalent interactions were investigated by 3D Hirshfeld surface analysis by the d _norm 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 in vitro 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 Staphylococcus aureus and Gram-negative Escherichia coli bacteria.

Keywords: Cu(II) complex; Hirshfeld surface; antibacterial activity; crystal structure; molecular docking; pyridoxal.

Grants and funding

The authors declare that financial support was received for the research, authorship, and/or publication of this article. The authors wish to thank the financial support of FAPDF (Process: 00193-00001849/2023-49), CNPq, UnB, and CAPES.