Synthesis, characterization, and dual applications of novel pyrazole-based ligands and their copper(II) complexes: anticancer, antimicrobial, and catalytic properties

Abstract

This study focuses on the synthesis, characterization, and evaluation of two novel pyrazole-based ligands, 2-(((3,5-dimethyl-1H-pyrazole-1-yl)methyl)amino)phenol L1 and 2-(bis((3,5-dimethyl-1H-pyrazole-1-yl)methyl)amino)phenol L2, and their corresponding copper(II) complexes. The ligands were synthesized through a multi-step alkylation process and complexed with copper(II) chloride to form six coordination complexes, CL1-1, CL1-2, CL1-3 for L1, and CL2-1, CL2-2, CL2-3 for L2. Structural characterization was performed using NMR, UV–Vis, and FT-IR spectroscopy, confirming the successful formation of the ligands and complexes. Biological evaluation revealed significant anticancer activity, with L1 exhibiting potent cytotoxicity against HCT116 colon cancer cells (IC50 = 13.28 ± 0.63 µM) and L2 showing selectivity toward SH-SY5Y brain cancer cells (IC50 = 22.01 ± 0.89 µM). Both ligands demonstrated moderate antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, while L2 exhibited strong antifungal activity against Candida glabrata (inhibition zone = 23.63 mm), outperforming the reference drug caspofungin. ADME studies provided insights into the pharmacokinetic profiles, indicating favorable drug-like properties for some complexes. Catalytic studies demonstrated the efficiency of the copper(II) complexes in the oxidation of 2,6-dimethylphenol, with the CL1-2 complex showing the highest catalytic activity. This work highlights the dual potential of pyrazole derivatives as both therapeutic agents and catalysts, bridging the fields of medicinal and coordination chemistry.