التفاصيل البيبلوغرافية
| العنوان: |
Partitioned energetics for propene internal rotation. |
| المؤلفون: |
Kundu, Tapanendu, Goodman, Lionel, Leszczynski, Jerzy |
| المصدر: |
Journal of Chemical Physics; 7/22/1995, Vol. 103 Issue 4, p1523, 7p |
| مصطلحات موضوعية: |
PROPENE, FORCE & energy |
| مستخلص: |
Energy partitioning in terms of symmetry components shows that σ-bonding changes contribute importantly to the energetics of the (∼700 cm-1) methyl torsional barrier in propene. This σ-conjugation effect, larger in propene than in acetaldehyde, has its primary origin in the partial unmaking of the bond between the methyl carbon and adjacent carbon atoms. The role of strain in generating torsional barriers is discussed. Rigid rotation leaves both molecules in a strained metastable conformation with the barrier primarily originating from π contributions to a repulsive nuclear virial. But overall energetics and hence barrier heights in the relaxed molecule are controlled by σ interactions. Extension to the propene+2 π cation provides insight into competition between σ and π interactions forming the barrier. In neutral propene dominant π-electron repulsion decreases the barrier, in the cation dominant σ-electron repulsion increases the barrier {predicted [MP2/6-311G(3df,2p)] height, 1241 cm-1}. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
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