The conformation and vibrational spectra including matrix isolation of 1,1,2-trichlorotrifluoroethane

doi:10.1016/0022-2860(87)87084-9

Journal of Molecular Structure

Volume 157, Issues 1–3, March 1987, Pages 73-91

Dedicated to Professor George C. Pimentel.

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Abstract

The IR spectra of 1,1,2-trichlorotrifluoroethane (FREON 113) have been observed in the vapour phase, in the liquid, in solution, at low temperatures and at high pressures between 4000 and 50 cm⁻¹. Additional IR spectra of the compound isolated in argon and nitrogen matrices at ca. 12 K have been recorded in the 1300–200 cm⁻¹ range. Raman spectra of the vapour, neat liquid and solid at various temperatures have been obtained. When compressed in a diamond anvil cell at ambient temperature, the compound forms a plastic phase at ca. 15 kbar, containing the same two conformers, C₁ and C_s, as in the vapour and the liquid. At a pressure exceeding 125 kbar an anisotropic crystal is formed containing the C₁ conformer. All the low temperature solid phases studied, appear to be plastic, and both conformers are present. No crystal containing one conformer has ever been achieved at low temperature, in spite of numerous attempts with different cooling techniques down to 15 K. Variation of the nozzle temperature of the matrix isolation unit between ambient temperature and 900 K gives rise to different conformer ratios in the matrices. By comparing band intensities at the various nozzle temperatures, the enthalpy difference of the two conformers is estimated to be 1.06 ± 0.11 kJ mol⁻¹ with C₁ as the more stable. A tentative assignment of IR and Raman bands to the C₁ and C_s fundamentals is carried out, supported by a normal coordinate calculation involving related molecules.

References (32)

B. Kakae et al.
Collect. Czech. Chem. Commun.
(1965)
R.A. Pethrick et al.
J. Chem. Soc. A
(1971)
G.O. Braathen
Spectrochim. Acta
(1985)
G.O. Braathen et al.
Spectrochim. Acta
(1986)
G.O. Braathen et al.
J. Mol. Struct.
(1986)
F.A. Miller et al.
Appl. Spectrosc.
(1970)
S. Mizushima et al.
Can. J. Phys.
(1975)
K. Kveseth
Acta Chem. Scand.
(1975)
D.L. Powell et al.
J. Mol. Struct.
(1983)
T. Woldbaek et al.
Acta Chem. Scand.
(1982)

S.D. Christian et al.

J. Chem. Phys.

(1976)

R.G. Snyder et al.

Spectrochim. Acta

(1965)

G. Glockler et al.

J. Chem. Phys.

(1941)

M. Iwasaki

Bull. Chem. Soc. Jpn.

(1959)

M. Iwasaki

Bull. Chem. Soc. Jpn.

(1959)

P. Klaeboe et al.

J. Mol. Spectrosc.

(1961)

H.E. Hallam et al.

J. Mol. Spectrosc.

(1964)

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Altitude-resolved volume mixing ratio profiles of CFC-113 have recently become available on a global scale with the Atmospheric Chemistry Experiment (ACE) satellite mission. However, the accuracy of the retrieval is currently limited by the uncertainties on the spectroscopic parameters of CFC-113. This paper reports on the geometrical structure, harmonic frequencies and intensities in the mid-infrared region of the two conformers of CFC-113 and the evaluation of whether theoretical calculations reproduce measurements. The calculations are performed using density functional theory at the B3LYP/6-311+G(3df) level. The molecular geometry parameters, the enthalpy difference and the potential barrier between conformers are calculated. The harmonic frequency of the normal modes of vibration are presented and accurately compared to experimental data. Overtones and combination bands are assigned in the 1200–2500 cm⁻¹ region.
Infrared and Raman spectroscopy applied to conformational equilibria; methods and recent results
1997, Journal of Molecular Structure
Common methods for conformational studies by vibrational spectroscopy include identification of band intensities by crystallization at low temperatures, intensity variations at variable temperatures and dissolution in solvents of different polarity. In addition, matrix isolation studies, crystallization under high pressure, formation of clathrates, temperature studies in liquid noble gases and chemometric methods can be applied.
These methods will be briefly discussed and are applied to some halomethyl dimethyl halosilanes which are presently being studied. The temperature dependent conformational equilibrium in chlorocyclohexane has been tested by chemometrics.
Conformational studies by vibrational spectroscopy: a review of various methods
1995, Vibrational Spectroscopy
The more important methods employed in conformational studies by infrared and Raman spectroscopy have been discussed. They include experimental methods to identify the observed vibrational bands with one or more conformers: crystallization under low temperature and high pressure conditions, variable temperature spectroscopy in the vapour and liquid states and matrix isolation spectroscopy with the hot nozzle method, including the effects of annealing and of photolysis. Differential scanning calorimetry is included, and certain molecules which have two or more solid phases each with a separate conformer are mentioned. An additional technique is spectral recordings of the compound as a solute in solvents of different polarity. Sometimes the formation of clathrates may favour one conformer. Experimental determinations of enthalpies and barriers using variable temperature studies and the analysis of torsional or puckering potentials are described. Computational methods including normal coordinate calculations, molecular mechanics and ab initio quantum chemical methods are included. The methods have been illustrated with compounds from the literature including substituted ethanes, cyclohexanes, cyclobutanes, neopentanes and related molecules.
The vibrational spectra including matrix isolation and conformations of 1-chloro-1-fluorocyclobutane and 1-chloro-1,2,2-trifluorocyclobutane
1993, Journal of Molecular Structure
The IR and Raman spectra of 1-chloro-1-fluorocyclobutane (CFCB) and 1-chloro-1,2,2-trifluorocyclobutane (CFCB) were recorded in various phases and at different temperatures, and included IR matrix spectra in argon and nitrogen matrices using the hot nozzle method. Both compounds have two conformers in the vapour and liquid states. CTFCB crystallized as one distinct conformer, while two conformers were present in all solid state spectra of CTFCB. The argon matrix spectrum of CFCB contained only one conformer at 13 K, suggesting a barrier lower than 5 kJ mol⁻¹ between the conformers. In both the argon and nitrogen matrix spectra of CTFCB two conformers were observed, although the concentrations of the less stable conformer were lower than in the vapour. This suggests a partial conversion to the stable conformer during deposition and a barrier slightly higher than 6 kJ mol⁻¹. The enthalpy difference ΔH° between the conformers was 2.2 kJ mol⁻¹ for CFCB in the liquid and 2.7 and 2.9 kJ mol⁻¹ in the vapour and liquid, respectively, for CTFCB. Ab initio calculations were carried out for both compounds using the 3-21G* and 6-31G* basis sets. For CFCB, both calculations gave the conformer with the fluorine atom equatorial as the more stable. For CTFCB, the smaller basis set also gave the conformer with equatorial fluorine as the more stable while the opposite was predicted with the larger basis set. Fairly complete assignments for both conformers of both compounds were made with the aid of normal coordinate calculations employing scaled ab initio force constants. Agreement was excellent between calculation and experiment for the case in which the more stable conformer was that with fluorine equatorial but impossible to achieve with fluorine axial.
Vibrational studies and ab initio calculations of the conformers of 1,2-dichloro-1,1,2-trifluoro-2-iodoethane
1993, Journal of Fluorine Chemistry
Infrared and Raman spectra of 1,2-dichloro-1,1,2-trifluoro-2-iodoethane have been recorded at ambient and sub-ambient temperatures. Tentative assignments of bands have been made. The energy difference between the conformers has been determined from the temperature dependence of the infrared spectral bands using the van't Hoff equation. The molecule has also been studied by ab initio molecular orbital calculations using an all-electron basis set as well as two basis sets employing effective core potentials. The calculated energy differences between the two conformers were found using MP2 single-point calculations with the geometry from the all-electron calculation. These computational results are in agreement with the experimental results.
Electron attachment to thermally excited trichlorotrifluoroethane (1, 1,2-C<inf>2</inf>Cl<inf>3</inf>F<inf>3</inf>)
1997, Journal of Physics D: Applied Physics

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¹: On leave from Department of Physical Chemistry, Slovak Technical University, 81237 Bratislava, Czechoslovakia, Č.S.S.R.

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The conformation and vibrational spectra including matrix isolation of 1,1,2-trichlorotrifluoroethane

Abstract

Collect. Czech. Chem. Commun.

J. Chem. Soc. A

Spectrochim. Acta

Spectrochim. Acta

J. Mol. Struct.

Appl. Spectrosc.

Can. J. Phys.

Acta Chem. Scand.

J. Mol. Struct.

Acta Chem. Scand.

J. Chem. Phys.

Spectrochim. Acta

J. Chem. Phys.

Bull. Chem. Soc. Jpn.

Bull. Chem. Soc. Jpn.

J. Mol. Spectrosc.

J. Mol. Spectrosc.