Synthesis and the antimicrobial activity of metalcarbene compounds of the triazole series

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Мetalcarbene compounds of a series of [1,2,4] and [1,2,3]triazoles have been synthesized to study their antimicrobial activity. Monocarbene complexes of palladium (9a) and copper(I) (9b,12,15), biscarbene complexes of palladium (4a) and copper(I) (4b,14), a carbenoid complex of cobalt (5) have been synthesized by the direct interaction of stable carbenes with transition metal salts or by analogous in situ reactions. The intermediate sterically hindered carbenes – [1,2,4]triazol-5-ylidenes 3a-c have been isolated in the individual state. Being intermediate in the synthesis of mesoionic complexes 9a,b 1-adamantyl-4-phenyl-[1,2,3]triazole has been synthesized by [3+2]-cycloaddition of 1-adamantylazide to phenylacetylene in the presence of the biscarbene complex of copper(I) iodide 14. Characteristic signals of the carbenoid carbon atoms are detected in the 13С NMR spectra of complexes in the range of 165-203 ppm. A high antimicrobial activity has been found for complexes 5.12; for compound 12 it corresponds to the minimal bacteriostatic concentration (MBsC) 15.6 mkG/mL, the minimal bactericidal concentration (MBcC) 31.2 mkG/mL (М. luteum), and MBsC 31.2 mkG/mL, MBcC 62.5 mkG/mL (S. aureus). The highest activity in the series studied is observed for the carbenoid complex of cobalt (5) on the test-culture of M. luteum (MBsC 15.6 mkG/mL and MBcC 31.2 mkG/mL), and on the test-culture of C. tenuis (the minimal fungistatic concentration is 7.8 mkG/mL and the minimal fungicidal concentration is 31.2 mkG/mL).