Vibrational spectroscopic studies on ion solvation of lithium perchlorate in propylene carbonate plus N,N-dimethylformamide mixtures

The infrared (IR) and Raman spectra are reported for solutions of lithium p erchlorate in propylene carbonate (PC), N,N-dimethylformamide (DMF) and PC + DMF mixtures. The band splittings of symmetric ring deformation for PC an d O=CN deformation for DMF suggest that there is a strong interaction betwe en lithium cations and solvent molecules. The solvent molecules have been a ssigned to two types, the free and complexed molecules. By a comparison of the intensity for the corresponding bands, it has been concluded that Li+ c ations are preferentially solvated by DMF molecules in the LiClO4/PC-DMF so lutions. This has been explained by the difference in values of donor numbe r. (C) 2000 Elsevier Science B.V. All rights reserved.