The effect of the cationic structures of chiral ionic liquids on their antimicrobial activities

In this study the significant effect of the cationic structures of ionic liquids on their antimicrobial efficacy has been shown. An analysis has been made for the structure of ammonium, alkylimidazolium, alkoxymethylimidazolium, and pyridinium chiral ionic liquids. The cationic structures of the discussed chiral ionic liquids and commonly used benzalkonium chloride were ranked in terms of antimicrobial activity. The broadest and the strongest spectrum of activities against microbes represent ammonium chlorides. Alkylimidazolium and alkoxymethylimidazolium chlorides exhibit activities also higher than the ones shown by benzalkonium chloride. These compounds can be successfully applied in antisepsis and disinfection. Contained in the structures of discussed chlorides chiral pool of (1R,2S,5R)-(−)-menthol has significant impact on strengthening the biological activity of CILs. Several chlorides with (±)-menthol derivative have been synthesized and their biological activity has been estimated. The racemic counterparts are much less effective than the optically active chlorides.