Structural and antimicrobial studies of antimony(III) halide complexes with thiophene-based thiosemicarbazones

A series of novel antimony(III) halide complexes with thiophene-based thiosemicarbazone ligands were synthesized in a 2:1 ligand-to-metal molar ratio via refluxing in methanol. The molecular formulations of the seven newly obtained complexes are as follows: [SbCl2(mu(2)-Cl)(kappa 1-S-Hattsc)(2)](2), [SbBr2(kappa 1-S-Httsc)(kappa 2-N3,S-Httsc)], [SbBr2(mu(2)-Br)(kappa 1-S-Hattsc)(2)](2), [SbI2(kappa 1-S-Htmtsc)(kappa 2-N3,S-Htmtsc)], [SbI2(kappa 1-S-Htetsc)(kappa 2-N3,S-Htetsc)], [SbI2(kappa 1-S-Hatmtsc)(kappa 2-N3,S-Hatmtsc)], and [SbI2(kappa 1-S-Hatetsc)(kappa 2-N3,S-Hatetsc)]. The structures of the synthesized complexes were confirmed by a combination of techniques, including melting point determination, molar conductivity measurements, elemental analysis, FT-IR, FT-Raman, UV-Vis spectroscopy, as well as 1H and 13C NMR spectroscopy. Thermal stability was assessed through thermogravimetric and differential thermal analyses (TG-DTA). The antimicrobial activities of the complexes were evaluated against both Gram-positive (Staphylococcus aureus ATCC 29213, Streptococcus mutans ATCC 25175, Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Salmonella typhimurium ATCC 14028). Notably, the complexes exhibited superior antimicrobial activity against E. coli, S. typhimurium, and S. mutans compared to the standard antibiotic gentamicin.