Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10564445 | Vibrational Spectroscopy | 2005 | 9 Pages |
Abstract
The broad SO stretching bands of DESO (1100-950Â cmâ1) were resolved in seven or eight components by deconvolution. On the basis of the previous studies of DESO in aqueous and non-aqueous solutions, the various components are assigned to free and associated species of DESO. The low-frequency component at â¼1007Â cmâ1 in FT-IR spectra of LiCl/DESO and LiClO4/DESO solutions is assigned to Li+-DESO complex formation. Moreover, the spectral changes of the SO stretching bands suggest that interaction between Li+ ion and DESO breaks partially down the self-associated structure of the solvent. In both IR and Raman spectra the curve fitting procedure in the CH stretching region (3000-2700Â cmâ1) gives five components, caused by antisymmetric and symmetric stretching vibrations of CH3 and CH2 groups of DESO. The low-frequency shift in solutions of lithium chloride indicates the existence of interactions between the CH2 group of DESO and the chloride anion. The curve fitting procedure performed for the out-of-plane bending of NO3â anion (840-820Â cmâ1) in IR spectra, and for the totally symmetric stretching vibration of ClO4â anion (950-920Â cmâ1) in Raman spectra has shown the coexistence of free ions and contact ion pairs. The comparison of experimental and theoretical calculated frequencies shows that the coordination of ClO4â in the ion pairs Li+ClO4â is monodentate. Density function theory (DFT) (B3LYP) methods have been used to determine the structure and energies of stable conformers. The optimised geometry corresponding to isolated molecules is the most stable conformation. With the basis sets of the 6-31+G(d) quality, the DFT calculated bond parameters and harmonic vibrations are predicted in a very good agreement with experimental data.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
S.A. Markarian, L.S. Gabrielian, A.L. Zatikyan, S. Bonora, A. Trinchero,