ChemInform Abstract: PRODUKTE DER ELEKTROCHEMISCHEN FLUORIERUNG VON AETHERN DES AETHYLENGLYKOLS

The geometric structures and conformational properties of bis(fluoromethyl) ether, CH2FOCH2F, bis(difluoromethyl) ether, CHF2OCHF2, and pentafluoromethyl ether, CF3OCHF2, have been studied with gas electron diffraction and quantum chemical methods (B3LYP/6-31G* and MP2 with 6-31G*, cc-pVTZ or 6-311G(2df) basis sets). IR(matrix) spectra have been recorded for CF3OCHF2. The most stable [sc,sc] conformer of CH2FOCH2F possesses C 2 symmetry with the C−F bonds of both CH2F groups in synclinal (sc, counterclockwise) orientation (φ(C−O−C−F) = 70(2)°). A small contribution (≤14%) of the [sc,−sc] form with C s symmetry cannot be excluded (−sc = synclinal, clockwise). CHF2OCHF2 exists in the gas phase as a mixture of two forms. In the main [ap,sp] conformer (82(8)%) one C−H bond is oriented antiperiplanar (ap), the other one synperiplanar (sp). This latter C−H bond nearly eclipses the opposite O−C bond with φ(C−O−C−H) = 18(2)°. Nearly eclipsed orientation of the C−H bond is also favored in CF3OCHF2 with φ(C−O−C−H) = 19(3)°. According to IR(matrix) spectra a small (8(3)%) contribution of the [ap] conformer with the C−H bond antiperiplanar relative to the opposite O−C bond is present at room temperture. The conformational properties of these fluorinated dimethyl ethers can be rationalized by orbital interaction energies derived from a natural bond orbital (NBO) analysis.

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“…The last two samples were purified by repeated trap-to-trap condensation. The purity of CF 3 OCHF 2 was checked by IR 21,22 and 19 F NMR spectra …”

Section: Methodsmentioning

confidence: 99%

Fluorinated Dimethyl Ethers, CH₂FOCH₂F, CHF₂OCHF₂, and CF₃OCHF₂: Unusual Conformational Properties

Ulic

Oberhammer

2004

J. Phys. Chem. A

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ChemInform Abstract: PRODUKTE DER ELEKTROCHEMISCHEN FLUORIERUNG VON AETHERN DES AETHYLENGLYKOLS

Cited by 1 publication

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Fluorinated Dimethyl Ethers, CH₂FOCH₂F, CHF₂OCHF₂, and CF₃OCHF₂: Unusual Conformational Properties

Fluorinated Dimethyl Ethers, CH₂FOCH₂F, CHF₂OCHF₂, and CF₃OCHF₂: Unusual Conformational Properties

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ChemInform Abstract: PRODUKTE DER ELEKTROCHEMISCHEN FLUORIERUNG VON AETHERN DES AETHYLENGLYKOLS

Cited by 1 publication

References 0 publications

Fluorinated Dimethyl Ethers, CH2FOCH2F, CHF2OCHF2, and CF3OCHF2: Unusual Conformational Properties

Fluorinated Dimethyl Ethers, CH2FOCH2F, CHF2OCHF2, and CF3OCHF2: Unusual Conformational Properties

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Fluorinated Dimethyl Ethers, CH₂FOCH₂F, CHF₂OCHF₂, and CF₃OCHF₂: Unusual Conformational Properties

Fluorinated Dimethyl Ethers, CH₂FOCH₂F, CHF₂OCHF₂, and CF₃OCHF₂: Unusual Conformational Properties