Antimicrobial Activity of Polyoxometalate Ionic Liquids against Clinically Relevant Pathogens

The activity of a new class of antimicrobials-polyoxometalate ionic liquids (POM-ILs)-is systematically investigated. The prototype POM-ILs feature Keggin-type anions (α-SiW₁₁ O₃₉ ^8- ) and tetraalkylammonium ions as active cationic species. Antimicrobial tests of the POM-ILs against important human pathogens show that variation of the alkyl chain length of the cation leads to significant changes in antimicrobial activity against the medically relevant Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and especially against the Gram-positive Staphylococcus aureus. Owing to the unique materials properties of the POM-ILs, such as high viscosity and water immiscibility, applications of antimicrobial surface coatings against airborne pathogens or for water decontamination can be envisaged. Furthermore, the combination of antimicrobially active cations with POM anions might afford new POM-ILs with two active components.