Synthesis and characterization of a cobalt(II) complex with 5-amino-1-tosyl-1h-1,2,4-triazole as a sulfonamide ligand: antibacterial and molecular docking studies

A new cobalt(II) complex, [Co(L)₄Cl₂]·2C₉H₁₀N₄O₂S (<b>1</b>), was prepared by reaction of CoCl₂·6H₂O with a sulfonamide, 5-amino-1-tosyl-1H-1,2,4-triazole (L), in double-distilled water and ethanol (1:1 v/v). The sulfonamide was characterized by elemental analysis, and infrared and ¹H-NMR spectroscopy, while the Co(II) complex was characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The X-ray structure analysis reveals that <b>1</b> consists of a mononuclear cobalt(II) complex, [Co(L)₄Cl₂], and two molecules of the co-crystallized ligand (5-amino-1-tosyl-1H-1,2,4-triazole). The cobalt(II) in <b>1</b> is coordinated by four triazole ligands and two chlorides in an octahedral environment. The antimicrobial activity and molecular docking of ligand and <b>1</b> were investigated. Antibacterial and antifungal activity studies of L and <b>1</b> show that both have moderate-to-significant activity against Gram-negative (<i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i>) and Gram-positive (<i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>) bacteria and fungi (<i>Aspergillus niger</i> and <i>Candida albicans</i>). According to molecular docking results, <b>1</b> could be a promising compound for developing antibacterial drugs. The docking results provide detailed evidence for the interactions of <b>1</b> with dihydropteroate synthase protein (DHPS). The microbial evaluation and molecular docking simulation results may lead to development of new drug candidates against bacterial and fungal strains.