Molecular structures, electronic properties, and energetics of fluorinated allenes and isomeric acetylenes

Journal Article · Thu Nov 16 04:00:00 EST 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100360a010· OSTI ID:7108606

Dixon, D A; Smart, B E ^[1]

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1. E. I. duPont de Nemours and Co. Inc., Wilmington, DE (USA)

The geometries, energies, and various electronic properties of the allenes CH{sub 2}=C=CH{sub 2}, CH{sub 2}=C=CHF, CHF=C=CHF, CH{sub 2}=C=CF{sub 2}, CHF=C=CH{sub 2}, CF{sub 2}=C=CF{sub 2} and the acetylenes CH{sub 3}C=CH, CH{sub 3}C=CF, CF{sub 3}C=CH, and CF{sub 3}C=CF have been calculated at the SCF level with a double-{zeta} basis set augmented by polarization functions on carbon. Final energies and properties were calculated with a fully polarized double-{zeta} basis set. Final energies were determined at the MP-2 level. The C=C and C-F bond lengths in the allenes decrease with increasing fluorine substitution. The CCC bond angles in CH{sub 2}=C=CHF, CHF=C=CHF, and CHF=C=CF{sub 2} all deviate about 1{degree} from collinearity. A series of isodesmic reaction enthalpies was calculated to derive heats of formation of all the fluorinated allenes and acetylenes and to evaluate their isodesmic stabilities. The effects of fluorination on the thermodynamic stabilities of allenes, acetylenes, and ethylenes are compared. Mulliken charge distributions, dipole moments, and ionization potentials were calculated for each molecule. The properties of the HOMO and LUMO's in the various fluorinated allenes and acetylenes are discussed.

• OSTI ID: 7108606
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:23; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400000* -- Chemistry
400200 -- Inorganic
Organic
& Physical Chemistry
ACETYLENE
ALKYNES
ALLENE
CALCULATION METHODS
DATA ANALYSIS
DIENES
ELECTRONIC STRUCTURE
ENERGY LEVELS
HYDROCARBONS
MATHEMATICAL MODELS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
POLYENES