The Use of AOBH‐DEHP Molecular Probe to Characterize BHDC Reverse Micelles Interfaces. Insights on the Interfacial Water Structure

Abstract

This work presents the use of the molecular probe: 3,6-bis (dimethylamino) acridinium bis-(2-ethylhexyl) phosphate salt, AOBH-DEHP. This probe is used to gain insights into the properties of the benzene/benzyl-n-hexadecyldimethylammonium chloride (BHDC)/water reverse micelles (RMs) interfaces. The techniques employed were absorption and emission spectroscopy in addition to the steady-state and, time-resolved fluorescence emission. For BHDC RMs without water addition, AOBH-DEHP can be used to determine the critical micellar concentration, CMC.Upon addition of water, we detect, at concentrations of BHDC lower < 1x10 À2 M, a proton transfer process from the AOBH + cation to the DEHP À anion producing AOB species. However, for [BHDC] > 10 À2 M, when the RMs is completely formed this process is reverted because water molecules at the interface interact with the cationic polar head of BHDC through the oxygen non-bonding electron pair enhancing their hydrogen bond ability and acidity, hence it can easily transfer a proton to AOB species to form AOBH + .[a] Dr.

Deciphering Solvation Effects in Aqueous Binary Mixtures by Fluorescence Behavior of 4-Aminophthalimide: The Comparison Between Ionic Liquids and Alcohols as Cosolvents

“…Since the early ‘80s, the formation of micelles in ILs took on relevance. Studies have been reported about these types of liquids used as a dispersing phase in micellar systems, , such as a polar solvent confined in reverse micelles. ,− In some studies, PILs are implemented as molecular probes to monitor reverse micelles. ,, Despite the versatility of these newly designed solvents, the greater limitation that ILs can have is the poor solubility of many solutes. Given this situation, it can be overcome by adding conventional cosolvents, taking into account that such an addition will tune the properties of the ILs as solvents.…”

“…18,26−29 studies, PILs are implemented as molecular probes to monitor reverse micelles. 19,30,31 Despite the versatility of these newly designed solvents, the greater limitation that ILs can have is the poor solubility of many solutes. Given this situation, it can be overcome by adding conventional cosolvents, taking into account that such an addition will tune the properties of the ILs as solvents.…”