Ionosome single entity electrochemical detection at a micro water/alkylphosphonium ionic liquid interface

Abstract

Ionic liquids (ILs) are composed of molecularly large organic ions that exist as supramolecular ion aggregates or contact ion pairs which contributes to their catalytic nature and control of metal nanoparticle growth. However, additions of small organic molecules may disrupt these aggregates. Herein, single entity electrochemistry (SEE) has been used to probe the formation of solvent microchannels that form in between IL and ion aggregates through the electrogeneration of ionosomes, i.e., water/ion-in-IL nanoclusters, at a micro water/IL (w|IL) immiscible interface. A concomitant increase in ionosome size was observed with increasing molecular solvent additions; however, diffusion NMR studies indicate that IL-ion aggregates do not shrink in size until a critical solvent level is achieved at ∼ 25% v/v solvent/IL indicating a ‘solvent tolerance’ limit. Thus, diffusion NMR and SEE paint two complementary pictures of the IL supramolecular system under solvent addition.