Understanding the microscopic structural organization of neat ammonium based ionic liquids through resonance energy transfer (RET) studies

Abstract

The present work aims at understanding the role of chemical structure of a cationic moiety of a given ionic liquid (IL) on the overall structural organization of the same IL in its fluid state through resonance energy transfer studies (RET). For this purpose, two branched alkyl group containing (butyl and octyl) ILs and one single alkyl chain (butyl) containing (non-branched) IL have been employed. During RET studies, neat ammonium-based ILs have been used as the donor and a charged solute rhodamine 6 G (R6G) as an acceptor as they satisfy the spectroscopic criteria needed for RET event to occur. The outcome of the present investigation depicts a more favorable RET interaction for a non-branched IL in comparison to that for branched ILs. The data has been explained by considering both electronic and steric effects. The current investigation illustrates that the structural organization of non- branched ILs are different from that of branched ILs.

Keywords

• Ionic liquids
• Resonance energy transfer
• Fluorescence spectroscopy
• Quenching