[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)

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 mu g/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. (C) 2017 Elsevier Inc. All rights reserved.