FTIR Spectroscopy Suggests a Revised Mode of Action for the Cationic Side-Chain Effect of Ionic Liquids

• DOI: 10.1021/acscombsci.8b00141
• Publication Date: 2018-12-31T19:59:48Z
• Authors: Patrick Mester; Christian Robben; Anna K. Witte; Roland Kalb; Monika Ehling-Schulz; Peter Rossmanith; Tom Grunert
• Keywords: Cationic polymerization; Side chain; Mode of Action

Over the past decades, ionic liquids (ILs) have gained considerable attention from scientific community because of their versatile and designable properties. As a result, there are numerous IL applications, not only in organic synthesis, catalysis, or extraction but also as active pharmaceutical ingredients novel antimicrobials. While effort has been put into developing quantitative structure–activity relationship (QSAR) models for toxicity prediction, little is known about actual mode action. In this study, Fourier transform infrared (FTIR) spectroscopy used to monitor induced molecular responses directly at cellular level. Investigation well-known cationic alkyl side-chain effect (increasing length leads increasing toxicity) imidazolium- ammonium-based ILs on two bacterial pathogens, enteropathogenic Escherichia coli (EPEC) methicillin-resistant Staphylococcus aureus (MRSA), surprisingly revealed distinct modes Contrary prior models, it was [TMC16A][Cl], where response membrane found, while with shorter lengths predominantly affected proteins. The results study highlight importance further direct investigations impact level improve prediction assess usefulness spectroscopic methods, such FTIR achieving goal.