Evaluation of antimicrobial properties of monocationic and dicationic surface-active ionic liquids

In the present study, a series of monocationic and dicationic surface-active ionic liquids (SAILs) were synthesized and characterized. The structures of SAILs were confirmed by spectral analyses of 1H NMR and 13C NMR. Additionally, the thermal properties of the synthesized monocationic and dicationic SAILs were determined using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Nevertheless, the crucial part of this work is to confirm the strong relationship between the structure, surface activity, and biological action of newly SAILs on bacteria (both G(-) and G(+)) and fungi. The elongation of the alkyl chain or linker in the imidazolium cation results in a decrease in the minimum inhibitory concentration (MIC). Dicationic SAILs containing more than eight carbon atoms in the linker showed antimicrobial activity. In contrast, a cutoff effect was observed for their monocationic analog.