Formation of Water-Soluble Pincer Silver(I)−Carbene Complexes:  A Novel Antimicrobial Agent

Silver(I)−2,6-bis(ethanolimidazolemethyl)pyridine hydroxide (<b>4a</b>) and silver(I)−2,6-bis(propanolimidazolemethyl)pyridine hydroxide (<b>4b</b>) are water-soluble silver(I)−carbene complexes that were synthesized in high yield by reacting silver(I) oxide with N-substituted pincer ligands <b>3</b> (<b>a</b> = 2,6-bis(ethanolimidazoliummethyl)pyridine diiodide, <b>b </b>= 2,6-bis(propanolimidazoliummethylpyridine)pyridine dibromide). The X-ray crystal structure of <b>4a</b> is a one-dimensional linear polymer, whereas the mass spectroscopy confirms a monomer in the gas phase. A change in the anion of <b>4a</b> from a hydroxide to a hexafluorophosphate formed a silver(I)−carbene complex <b>4c</b> that is dimeric in structure and insoluble in water. The bactericidal activities of the water-soluble silver(I)−carbene complexes were found to be improved over that of silver nitrate.