lithium-tetrafluoroborate and propylene-carbonate

FTIR (Fourier transformed infrared) spectra have been collected and analyzed for solutions of lithium tetrafluoroborate in propylene carbonate (PC), diethyl carbonate (DEC), and PC+DEC mixtures. It has been shown that the carbonyl stretch bands of PC and DEC, the ring of PC and the ether oxygen stretch bands of DEC are all very sensitive to the interaction between Li(+) and the solvent molecules. New shoulders appear and the original bands split with the addition of LiBF4, indicating that a strong interaction between Li(+) and molecules of PC and DEC exists through the oxygen group of C=O and ring of PC and both C=O oxygen and ether oxygen atoms of DEC. In addition, no preferential solvation of Li(+) in LiBF4/PC+DEC solutions was detected.

Topics: Borates; Diethyl Pyrocarbonate; Models, Molecular; Molecular Conformation; Propane; Solutions; Spectroscopy, Fourier Transform Infrared

FTIR (Fourier transformed infrared) spectra have been collected and analyzed for solutions of lithium tetrafluoroborate in propylene carbonate (PC), N,N-dimethylformamide (DMF), and PC+DMF mixtures. The band splitting and symmetric ring deformation for PC and O=C-N deformation for DMF suggest that there is a strong interaction between lithium cations and solvent molecules. The solvent molecules have been assigned to two types, the free and complexed molecules. By a comparison of the intensity for the corresponding bands, it has been concluded that Li(+) cations are preferentially solvated by DMF molecules in the LiBF4/PC+DMF solutions. This has been explained by the difference in values of donor number (DN).

Topics: Borates; Dimethylformamide; Lithium; Propane; Solutions; Solvents; Spectroscopy, Fourier Transform Infrared