Vibrational spectra of imidazolium tetrafluoroborate ionic liquids
| Autor: | John S. Wilkes, W. Robert Carper, Zhizhong Meng, Norman E. Heimer, Rico E. Del Sesto |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Tetrafluoroborate Hydrogen bond Infrared spectroscopy Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Ion chemistry.chemical_compound chemistry Computational chemistry Ionic liquid Materials Chemistry Side chain Physical chemistry Density functional theory Physical and Theoretical Chemistry Spectroscopy Alkyl |
| Zdroj: | Journal of Molecular Liquids. 124:84-95 |
| ISSN: | 0167-7322 |
| DOI: | 10.1016/j.molliq.2005.08.004 |
| Popis: | The Raman and infrared spectra of a series of 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids ([C2-4MIM][BF4]) are reported and analyzed using Density Functional Theory (DFT) and RHF methods at the 6-311+G(2d,p) computational level. The B3LYP (DFT) and RHF calculations reproduce the vibrational spectra of 1-ethyl-3-methyl imidazolium tetrafluoroborate [EMIM][BF4], 1-propyl-3-methyl imidazolium tetrafluoroborate [PMIM][BF4] and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4] using correction factors of 0.963–0.967 (DFT) and 0.913–0.916 (RHF) with correlation coefficients R2 of 0.999 using the fully optimized structures. Theoretical (DFT) alkyl side chain conformational changes in the 1-alkyl-3-methyl tetrafluoroborate ionic liquids have only a limited effect on the theoretical gas phase vibrations. The gas phase molecular structures of the [C2–4MIM][BF4] ion pairs suggest hydrogen bonding interactions between the fluorine atoms of the BF4− anion and the C2 hydrogen on the imidazolium ring. Additional interactions are observed between [BF4] and H atoms on the adjacent alkyl side chains in all polymorphic structures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect