Cationic Au(I) complexes with aryl-benzothiazoles and their antibacterial activity.

Two cationic Au(I) complexes derived from aryl-benzothiazoles, namely [(PPh3)Au(pbt)](OTf) (1) and [(PPh3)Au(qbt)](OTf) (2) (where pbt = 2‑(pyridyl)benzothiazole and qbt = (quinolyl)benzothiazole, and OTf− = trifluoromethanesulfonate anion), have been synthesized and structurally characterized by X-ray crystallography. Both complexes exhibit strong antibacterial effects against Gram-negative bacteria such as Acinetobacter baumannii and Pseudomonas Aeruginosa. Results of examination of the reactions of 1 and 2 indicate that these cationic Au(I) complexes rapidly cross the bacterial membrane and exert drug action by disrupting cellular function(s) through binding of cytosolic thiol-containing peptides (such as glutathione) and proteins to the highly reactive (PPh3)Au+ intermediate formed upon in situ dissociation of pbt or qbt.