Selective Chirality Transfer to the Bis(trifluoromethylsulfonyl)imide Anion of an Ionic Liquid

Abstract

Chirality transfer from the chiral molecule (R)‐1,2‐propylene oxide to the achiral anion of the 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid is observed. The chiral probe selectively affects one part of the binary ionic liquid, i. e., it has previously been shown experimentally and theoretically that this particular imidazolium cation can be affected by chirality transfer, but in the present system chirality is almost exclusively transferred to the anion and not to both parts of the solvent (anion and cation). This observation is of high relevance because of its selectivity and because anion effects are usually much more important in ionic liquid research than cation effects. From ab initio molecular dynamics simulations, a conformational analysis and dissected vibrational circular dichroism spectra are obtained to study the chirality transfer. While in the neat ionic liquid two mirror imaged trans conformers of the anion occur almost equally, we observe an excess of one of these conformers in the presence of the chiral solute, causing optical activity of the anion. Although the cis conformers are not tremendously affected by the chirality transfer, they gain in total population when (R)‐1,2‐propylene oxide is dissolved in the ionic liquid.

Red Circularly Polarized Luminescence from Dimeric H-Aggregates of Acridine Orange by Chiral Induction

“…Herein, we explore these aspects through a joint experimental and computational investigation of acridine orange bound onto chiral templates made of L-and D-isomers of valine-based amphiphiles. Computational methods such as MD simulations have recently been used to study chirality transfer to an ionic liquid, 40 and to obtain the chiral sum frequency generation response of water around a protein. 41,42 Amphiphiles, C 16 -L-Val and C 16 -D-Val (Figure 1A), containing head groups based on L-/D-valine and hexadecyl tails, are considered for the investigations.…”