Inhibition of microbial steel corrosion by quaternary salts of imidazoquinolinium

The 2.3-diaryl-4.5-dihydro-imidazo[1.2-a]quinolinium-3 bromides were tested as biocides and inhibitors of microbial corrosion of low-carbon steel induced by bacteria of strain Desulfo­vibrio sp. M-4.1. The degree of metal protection against corrosion induced by sulfate-reducing Desulfovibrio sp. M-4.1 bacteria is 84.6-92.4%. 2-(para-tolyl)-3-(41-methoxyphenyl)-4.5-dihydro-imidazo[1.2-a]quinolinium bromide demonstrated the best protective effect. It was established that sulfate-reducing bacteria of Desulfovibrio sp. M-4.1 strain are sensitive to 2.3-diaryl-4.5-dihydro-imidazo[1.2-a]quinolinium-3 bromides. Under the action of imidazoquinolinium quaternary salts, the inhibition zones of bacterial growth have the diameters of 24.7–45.5 mm. Quaternary salts of imidazoquinolinium completely suppress the growth of sulfate-reducing Desulfovibrio sp. M-4.1 bacteria in plankton and significantly affect the formation of biofilm (the number of cells decreases by 6–8 orders compared to the control sample) under conditions of microbial corrosion. Suppression of the sulfate-reducing activity of Desulfovibrio sp. M-4.1 bacteria by quater­nary salts of imidazoquinolinium (by 88.8-91.6%) was proven. The effectiveness of the quaternary salts was discussed with account of the calculation results of molecular descriptors.