Systematic Synthesis and Properties Evaluation of Dicationic Ionic Liquids, and a Glance Into a Potential New Field

Abstract

Dicationic ionic liquids (DILs), a subset of the ionic liquid (IL) family, have attracted growing interest in recent years, and the range of applications within which they are investigated is constantly expanding. However, data which allows structure to property correlation of a DIL is still limited, and thus selecting an appropriate salt to address a specific challenge can be problematic. In comparison to traditional ILs, DILs physico-chemical properties can be tuned by changing the length and type of spacer which connects the cationic heads as well as the type of cation. This in turn could give rise to symmetrical or asymmetrical DILs. In this work, a systematic study of a homogeneous class of 12 dibromide DILs and 12 di-carboxylate salts has been performed. The latter class of DILs were also compared to mono cation derivatives. The different traditional exchange methods to prepare carboxylate DILs have been evaluated and an insight into the drawbacks encountered is also presented. Prepared DILs were characterized (NMR, TGA, DSC) allowing the influence of the structure on their thermal stability to be understood. Most DILs were obtained as solid salts after careful drying. For some of these compounds, a new possible application was studied, namely their use as hydrogen bond acceptors (HBA) of deep eutectic mixtures, showing again some significant structural related effects.

Cathodic Behaviour of Dicationic Imidazolium Bromides: The Role of the Spacer

“…DILs and reference DTs and TILs were synthesized following literature methods . Their spectral data (Tables 2 and 3) were in accordance with those reported in the literature .…”

An insight into the intermolecular vibrational modes of dicationic ionic liquids through far-infrared spectroscopy and DFT calculations

“…3,3 0 -(Butane-1,4-diyl)bis(1-butyl-1H-imidazol-3-ium) bromide ([BIC 4 IB] 2+ + 2Br À ), 3,3 0 -(pentane-1,5-diyl)bis(1-butyl-1H-imidazol-3-ium) bromide ([BIC 4 IB] 2+ + 2Br À ) and 3,3 0 -(hexane-1,6-diyl)bis(1-methyl-1H-imidazol-3-ium) bis(triuoromethane) sulfonamide ([MIC 6 IM] + + 2Tf 2 N À ) were prepared following previously published procedures. 52,53 FIR measurements FIR spectra were recorded with a FT/IR-6800 Fourier Transform Infrared Spectrometer (Jasco).…”

Fe-functionalized paramagnetic sporopollenin from pollen grains: one-pot synthesis using ionic liquids

“…Recently, some of us reported a novel procedure for the separation of sporopollenin from the other pollen components, using ionic liquids (ILs) 13 . ILs are organic salts which are liquid below 100 °C and, thanks to the possibility to tailor their physico-chemical properties by changing the constituting ion, found use in a wide range of different applications during the last two decades [14][15][16][17][18][19] .…”