[Au(pyb-H)(mnt)]: A novel gold(III) 1,2-dithiolene cyclometalated complex with antimicrobial activity (pyb-H = C-deprotonated 2-benzylpyridine; mnt = 1,2-dicyanoethene-1,2-dithiolate)

Abstract The novel heteroleptic cyclometalated complex [Au III (py b -H)(mnt)] ( 1 ; py b -H = C-deprotonated 2-benzylpyridine; mnt  = 1,2-dicyanoethene-1,2-dithiolate) was tested against a panel of ten Gram positive (belonging to the Staphylococcus , Streptococcus spp. and Bacillus clausii ), Gram negative ( E. coli , K. pneumoniae , P. aeruginosa ) bacteria and three yeasts belonging to the Candida spp. Complex 1 showed a remarkable bacteriostatic antimicrobial activity against staphylococci, with Minimum Inhibitory Concentration (MIC) values of 1.56 and 3.13 μg/mL for S. haemoliticus and S. aureus , respectively. Spectroscopic and electrochemical measurements, supported by Density Functional Theory (DFT) calculations, were exploited to fully investigate the electronic structure of complex 1 and its relationship with the antimicrobial activity.