Crystal Structure, Vibrational Spectroscopy and ab Initio Density Functional Theory Calculations on the Ionic Liquid forming 1,1,3,3-Tetramethylguanidinium bis{(trifluoromethyl)sulfonyl}amide

Rolf W. Berg, Anders Riisager, Olivier Nguyen van Buu, Rasmus Fehrmann, Pernille Harris, Alina Agnieszka Tomaszowska, K. R. Seddon

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The salt 1,1,3,3-tetramethylguanidinium bis{(trifluoromethyl)sulfonyl}amide, [((CH3)(2)N)(2)C=NH2](+)[N(SO2-CF3)(2)](-) or [tmgH][NTf2], easily forms an ionic liquid with high SO2 absorbing capacity. The crystal structure of the salt was determined at 120(2) K by X-ray diffraction. The structure was found to be monoclinic, space group P2(1)/n with a = 11.349(2), b = 11.631(2), c = 11.887(2) angstrom, and beta = 90.44(3)degrees. Raman and IR spectra are presented and interpreted. The results are interpreted using ab initio quantum mechanics calculations that also predicted vibrational spectra. The relationship between the transoid (C-2 symmetry) structure of the [NTf2](-) ion and the conformationally sensitive bands is discussed.
Original languageEnglish
JournalJournal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
Issue number26
Pages (from-to)8878-8886
Publication statusPublished - 2009

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