Differences in Ion Interactions for Isoelectronic Ionic Liquid Homologs.

Specific cation-anion interactions for two pairs of isoelectronic ionic liquids (ILs) have been investigated using nuclear Overhauser effect (NOE) 2D NMR methods to explore proximities between ions. The four ILs comprise the bis(trifluoromethylsulfonyl)amide anion paired with the following cations: triethyloctylammonium, (2-ethoxyethoxy)ethyltriethylammonium, triethyloctylphosphonium, and (2-ethoxyethoxy)ethyltriethylphosphonium. Substantial interactions are observed between the anion (19)F nuclei and all of the protons on the triethyl chains for each of the four cationic head groups.

Comparing intermediate range order for alkyl- vs. ether-substituted cations in ionic liquids.

X-ray scattering data from four pairs of ionic liquids (ILs) are compared. The alkyl-substituted cations show a first sharp diffraction peak between 3 and 4 nm(-1) that is not observed for ILs having cations with ether- or hydroxy-substitutions. These observations indicate a significant difference in the intermediate range order for these liquids.

Ionic liquids and solids with paramagnetic anions.

Four paramagnetic ionic compounds have been prepared and their magnetic, structural and thermal properties have been investigated. The four compounds are methylbutylpyrrolidinium tetrachloroferrate(III) ([Pyrr(14)](+)/[FeCl(4)](-)), methyltributylammonium tetrachloroferrate(III) ([N(1444)](+)/[FeCl(4)](-)), butylmethylimidazolium tetrachloroferrate(III) ([bmim](+)/[FeCl(4)](-)) and tetrabutylammonium bromotrichloroferrate(III) ([N(4444)](+)/[FeBrCl(3)](-)). Temperature-dependent studies of their magnetic behaviors show that all four compounds are paramagnetic at ambient temperatures.