Influence of lithium salt on the structure and dynamics of deep eutectic solvents

Choline chloride based two different deep eutectic solvent (DES) have been synthesized and different mole fractions of LiNTf₂ salt were added. Steady state fluorescence and electron paramagnetic resonance (EPR) spectroscopy are employed to estimate the polarities of the mediums. Solvation dynamics of a dipolar dye C153 was carried out to understand the solvation process of DESs in presence of lithium salts. Time resolve fluorescence anisotropy technique is used to study the rotational relaxation dynamics of neutral, dipolar and charged dye in both DESs containing lithium salt which exhibit significantly different behaviour with increase in lithium salt concentration. (author)