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Characteristic of structures and π-hydrogen bond of dimers C2H4-nFn-HF (n=0,1,2).
- Source :
- Journal of Chemical Physics; 11/8/2004, Vol. 121 Issue 18, p8775-8781, 7p, 2 Diagrams, 4 Charts, 1 Graph
- Publication Year :
- 2004
-
Abstract
- By the counterpoise-correlated potential energy surface method (interaction energy optimization), five structures of the C<subscript>2</subscript>H<subscript>4-n</subscript>F<subscript>n</subscript>-HF (n=0,1,2) dimers with all real frequencies have been obtained at MP2/aug-cc-pVDZ level. The influence of F substituent effect on the structure and π-hydrogen bond of dimer has been discussed. For C<subscript>2</subscript>H<subscript>4-n</subscript>F<subscript>n</subscript>-HF (n=1,2), the π-hydrogen bonds are elongated comparing with that for C<subscript>2</subscript>H<subscript>4</subscript>-HF. For C<subscript>2</subscript>H<subscript>3</subscript>F-HF, g-C<subscript>2</subscript>H<subscript>2</subscript>F<subscript>2</subscript>-HF, cis-C<subscript>2</subscript>H<subscript>2</subscript>F<subscript>2</subscript>-HF, the π-hydrogen bonds are further deformed. These changes (elongate, shift, and deformation) of π-hydrogen bond mainly come from deformation of π-electron cloud of C==C bond. The π-electron cloud is pushed towards the one C atom, the π H-bond shift also to the C direction. Since the two lobes of π-electron cloud have deviated slightly from the molecular vertical plane passing through C==C bond, the π-hydrogen bond is sloped. Intermolecular interaction energies of the dimers are calculated to be -3.9 for C<subscript>2</subscript>H<subscript>4</subscript>-HF, -2.8 for C<subscript>2</subscript>H<subscript>3</subscript>F-HF, -2.1 for g-C<subscript>2</subscript>H<subscript>2</subscript>F<subscript>2</subscript>-HF, -1.6 for cis-C<subscript>2</subscript>H<subscript>2</subscript>F<subscript>2</subscript>-HF, -1.3 kcal/mol for trans-C<subscript>2</subscript>H<subscript>2</subscript>F<subscript>2</subscript>-HF, at CCSD(T)/aug-cc-pVDZ level. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Subjects :
- POTENTIAL energy surfaces
HYDROGEN bonding
DIMERS
QUANTUM chemistry
ELECTRONS
PHYSICS
Subjects
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 121
- Issue :
- 18
- Database :
- Complementary Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 14909714
- Full Text :
- https://doi.org/10.1063/1.1799615