Vibrational spectroscopic study on ion solvation and association of lithium perchlorate in 4-methoxymethyl-ethylene carbonate

Solvation interaction and ion association in solutions of lithium perchlorate/4-methoxymethyl-ethylene carbonate (MEC) have been studied by using Infrared and Raman spectra as a function of concentration of lithium perchlorate. The splitting of ring deformation band and ring ether asymmetric stretching band, and the change of carbonyl stretching band suggest that there should be a strong interaction between Li+ and the solvent molecules, and the site of solvation should be the oxygen atom of carbonyl group. The apparent solvation number of Li+ was calculated by using band fitting technique. The solvation number was decreased from 3.3 to 1.1 with increasing the concentration of LiClO4/MEC solutions. On the other hand, the band fitting for the ClO4-, band revealed the presence of contact ion pair, and free ClO4-, anion in the concentrated solutions.