Silver(I) N-heterocyclic carbene complexes: synthesis, characterization and antibacterial activity

Five new silver complexes having bidentate N-heterocyclic carbene ligands were synthesized and characterized. Four of the ligands used are neutral, having an alcohol group on one of two nitrogen of the heterocycle [NHC-OH], the fifth, having a ligand alkoxide, is mono-anionic [NHC-O]. A study on the rate of hydrolysis of complexes synthesized, showed that they are stable to hydrolysis even after 24 hours. Probably, the pincer effect of both [NHC-OH] and [NHC-O] ligands stabilize these compounds. All the synthesized complexes do not show cytotoxicity, but they have a significant anti-microbial activity. They were tested on Escherichia coli and Bacillus subtilis and data obtained demonstrate that the synthesized Ag-complexes are very promising candidates to be used as antimicrobial compounds.