‘Silver bullets’ in antimicrobial chemotherapy: Synthesis, characterisation and biological screening of some new Ag(I)-containing imidazole complexes

Simple synthetic routes are given to the Ag(I) complexes, [Ag2(imH)4](salH)2 (imH = imidazole; salH2 = salicylic acid), [Ag(MeNO2imH)2]ClO4 · nH2O (MeNO2imH = 2-methyl-5-nitroimidazole; n = 1, 3), [Ag(NO2im)] (NO2imH = 5-nitroimidazole) and [Ag(apim)]ClO4 (apim = 1-(3-aminopropyl)imidazole). X-ray crystal structures of [Ag2(imH)4](salH)2, [Ag(MeNO2imH)2]ClO4 · H2O and [Ag(apim)]ClO4 were obtained. The new Ag(I) complexes and related known Ag(I) imidazolates were screened for their growth inhibitory effects (in vitro) against the pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli and also the fungal pathogen Candida albicans. [Ag2(imH)4](salH)2, in comparison to the prescription drug silver sulfadiazine, had significantly better anti-bacterial qualities, whilst against the fungus C. albicans it was 47 times more potent than the marketed drug ketoconazole.