Geometry and vibrational frequencies of the lithium triflate ion pair: An ab initio study

Journal Article · Thu Nov 04 00:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100146a011· OSTI ID:5534218

Gejji, S P; Hermansson, K; Tegenfeldt, J; Lindgren, J ^[1]

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1. Uppsala Univ. (Sweden)

The optimized geometry, harmonic vibrational frequencies, and infrared absorption intensities of the lithium trifluoromethanesulfonate (triflate) ion pair, CF[sub 3]SO[sub 3]-Li have been investigated using the ab initio self-consistent Hartree-Fock and correlated second-order Moller-Plesset perturbation theory with the 6-31G* and lower basis sets. In the optimized structure the lithium cation is bound to two of the oxygens of the SO[sub 3] group forming a bidentate complex with C[sub s] symmetry. A local minimum with a monodentate structure was obtained in the HF/3-21G* calculations. The energy difference between the mono- and bidentate structures of the complex is predicted to be nearly 39 kJmol[sup [minus]1] in this basis. A splitting of 230 and 158 cm[sup [minus]1] is obtained for the antisymmetric SO[sub 3] stretching for the bi- and monodentate coordination of the lithium cation with the free anion, respectively. The infrared spectrum of lithium triflate in poly(propylene oxide) shows a splitting of 43 cm[sup [minus]1]. The strong interaction of the metal cation with the anion in the 1:1 complex thus overemphasizes the [open quotes]splitting behavior[close quotes] observed for lithium triflate dissolved in polymers. In the bidentate (MP2/6-31G*) complex the symmetric SO[sub 3] stretching shows a downshift of 38 cm[sup [minus]1], in contrast to an upshift of 47 cm[sup [minus]1] for the monodentate complex. 22 refs., 2 figs., 6 tabs.

• OSTI ID: 5534218
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 97:44; ISSN 0022-3654
• Country of Publication: United States
• Language: English

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25 ENERGY STORAGE
30 DIRECT ENERGY CONVERSION
37 INORGANIC
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PHYSICAL AND ANALYTICAL CHEMISTRY
LITHIUM COMPLEXES
INFRARED SPECTRA
MOLECULAR STRUCTURE
VIBRATIONAL STATES
ELECTRIC BATTERIES
FUEL CELLS
HARTREE-FOCK METHOD
IONS
ORGANIC POLYMERS
PERTURBATION THEORY
THEORETICAL DATA
CALCULATION METHODS
CHARGED PARTICLES
COMPLEXES
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DIRECT ENERGY CONVERTERS
ELECTROCHEMICAL CELLS
ENERGY LEVELS
EXCITED STATES
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NUMERICAL DATA
ORGANIC COMPOUNDS
POLYMERS
SPECTRA
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400102 - Chemical & Spectral Procedures
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