Characteristic Spectroscopic Features because of Cation-Anion Interactions Observed in the 700-950 cm-1 Range of Infrared Spectroscopy for Various Imidazolium-Based Ionic Liquids

An innovative deep eutectic solvent: chalcogen bonding as the primary driving force

Chalcogen bonding (ChB) interactions have drawn intensive attention in the last few decades as interesting alternatives to hydrogen bonding. The applications of ChB were mostly centered on the solid state and have rarely been explored in solution. In this work, a novel strategy for forming ChB-based deep eutectic solvents (DESs) was exploited. We set forth the formation, physicochemical properties, and interaction sites in detail. This work not only provides a new idea to design DES systems but also to exploit the potential application of ChB complexes.

Designing a TiO2-MoO3-BMIMBr nanocomposite by a solvohydrothermal method using an ionic liquid aqueous mixture: an ultra high sensitive acetaminophen sensor

This study shows a simplistic, efficient procedure to synthesize TiO₂-MoO₃-BMIMBr nanocomposites. Powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy have all been used to completely analyse the materials. The detection of acetaminophen (AC) has been examined at a modified glassy carbon electrode with TiO₂-MoO₃-BMIMBr nanocomposites. Moreover, the electrochemical behavior of the nanocomposite modified electrode has been studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The linear response of AC was observed in the range 8.26-124.03 nM. The sensitivity and detection limits (S/N = 3) were found to be 1.16 μA L mol^-1 cm^-2 and 11.54 nM by CV and 24 μA L mol^-1 cm^-2 and 8.16 nM by DPV respectively.

Infrared and Terahertz Spectroscopic Investigation of Imidazolium, Pyridinium, and Tetraalkylammonium Tetrafluoroborate Ionic Liquids

We performed terahertz time-domain spectroscopy and infrared spectroscopy of imidazolium-based, pyridinium-based, and tetraalkylammonium-based tetrafluoroborate ionic liquids to study their characteristic intermolecular and intramolecular vibrational modes to clarify interactions between various cations and the tetrafluoroborate anion. It was found that the central frequency of the intermolecular vibrational band for these ionic liquids has a relatively high frequency, ranging from 90 to 100 cm^-1. In the 900-1150 cm^-1 range, the intramolecular vibrational absorption band of the 3-fold degenerate mode of tetrafluoroborate anions in the ionic liquids was observed. Although the tetrafluoroborate anion is attributable to one of the weakly coordinated anions, the spectroscopic splitting behavior of the 3-fold degenerate mode differs depending on the cation species. It was revealed that the degenerate mode is very sensitive to local interactions between the tetrafluoroborate anion and each cation.

An emerging deep eutectic solvent based on halogen-bond

A new deep eutectic solvents (DES) driven by halogen-bond was exploited. A family of eutectic mixtures in liquid state were obtained by combination of quaternary ammonium salts and dihalogens. The...

Triethylsulfonium-Based Ionic Liquids Enforce Lithium Salts Electrolytes

The demand for energy cheap production and efficient storage is huge nowadays. Sulfonium-based ionic liquids were shown to exhibit a useful set of physical-chemical and electrochemical properties which make them...

Infrared Spectroscopy in the Middle Frequency Range for Various Imidazolium Ionic Liquids-Common Spectroscopic Characteristics of Vibrational Modes with In-Plane +C(2)-H and +C(4,5)-H Bending Motions and Peak Splitting Behavior Due to Local Symmetry Breaking of Vibrational Modes of the Tetrafluoroborate Anion

Various alkyl-methylimidazolium ionic liquids (ILs) were inspected using infrared spectroscopy in the middle frequency range. In the 1050-1200 cm^-1 range, there is a skeletal vibrational mode accompanied with a large in-plane ⁺C(2)-H bending motion and ⁺C(4)-H and ⁺C(5)-H motions, and in the 1500-1650 cm^-1 range, there are two skeletal vibrational modes with in-plane ⁺C(4,5)-H bending motions. Interestingly, in both ranges, we found that skeletal vibrational modes with a large in-plane ⁺C(2)-H bending motion and in-plane ⁺C(4,5)-H bending motions are insensitive to increases in the basicity of anions or the strengthening of hydrogen bond-type interactions, and the behaviors are completely different from those in the ⁺C-H stretching vibrational modes in the 3000-3200 cm^-1 range and the skeletal vibrational modes with large out-of-plane ⁺C-H motions in the 700-950 cm^-1 range. Furthermore, in alkyl-methylimidazolium tetrafluoroborate [C _n mim⁺][BF₄ ^-] ILs, we found that absorption due to the (threefold) degenerate vibrational mode of [BF₄ ^-] was observed as a broad absorption band with three splitting peaks in the 900-1150 cm^-1 range as a result of local symmetry breaking due to the cation-anion interactions.