Synthesis, characterization and antimicrobial activity of Cr (III), Co (II) and Ni (II) complexes with 2-thiazoline-2-tiol derivative ligands against bacteria and yeasts of clinical importance

Abstract: Four novel Cr (III), Co (II) and Ni (II) complexes with 2-thiazoline-2-tiol derivative ligands were synthesized and characterized using elemental, physiochemical, and spectroscopy analytical methods. The results showed the formation of ligands coordinated by sulfur atoms of the C = S bond to the L1 ligand and by the sulfur atom of the C-S bond and/or nitrogen of the intra C-ring bond of the L2 ligand. The activity of the complexes against Gram-negative, Gram-positive bacteria and yeasts of clinical importance was evaluated by broth microdilution method. The best result was obtained to L2-Ni compound against E. cloacae (Minimal Inhibitory Concentration (MIC) = 62.5 µg/mL). Additionally, the compounds showed anti-Candida activity (MIC values ranging from 250 to 500 µg/mL), except the L1-Cr that was not active against any tested microorganism.

Key words
1,2-bis-bis (2-thiazolin-2-isulfanyl) ethane; antimicrobial activity; hidrotris (2-mercaptothiazolyl) borate; complexes