Synthesis, characterization and antimicrobial activity of silver(I) complexes of hydroxymethyl derivatives of pyridine and benzimidazole

Three new silver(I) complexes of 4-(hydroxymethyl)pyridine (4-CH2OHpy), 2,6-di(hydroxymethyl)pyridine (2,6-di(CH2OH)py) and 2-(hydroxymethyl)benzimidazole (2-CH2OHbim) were synthesized. These complexes, with the general formula [Ag(L)2]NO3, were characterized by IR, NMR (1H and 13C) spectroscopy and elemental analysis. ESI-MS spectrometry was used in some cases. The crystal structure of [Ag(4-CH2OHpy)2]NO3 was determined by single crystal X-ray diffraction analysis. The complex demonstrates the slightly bent N1–Ag1–N2 coordination geometry (167.22(4)°) and consists of one nitrate anion and one silver ion coordinated by two 4-(hydroxymethyl)pyridine (4-CH2OHpy) ligands via N atoms. The series of three silver(I) complexes and the corresponding free ligands was tested for their antibacterial and antifungal activities, screened in vitro against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228 and Candida albicans ATCC 10231. All the silver(I) complexes demonstrated considerable activity, especially against C. albicans (with MIC values 10–20 mg l−1).