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Ab initio studies of structural features not easily amenable to experiment. 17. The molecular structures of some strained cyclic hydrocarbons and estimates of their strain energies

✍ Scribed by C. Van Alsenoy; J. N. Scarsdale; Lothar Schäfer

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
671 KB
Volume
3
Category
Article
ISSN
0192-8651

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✦ Synopsis

Abstract

The molecular structures of tricyclohexane, norbornane, quadricyclane, and cubane were completely refined by standard ab initio force relaxation on the 4‐21G level. The results can be used as a basis to interpret some contradictory experimental reports found in the literature and to establish some hitherto unobserved structural trends involving the CC and CH bond distances of the cases studied. Group Delta;E values for C(H)~3~(C), C(H)~2~(C)~2~, and C(H)(C)~3~ (Benson's notation) derived from the total energies of the completely relaxed 4‐21G geometries of a number of unstrained hydrocarbons are also listed. The values are used to estimate the strain energies of the systems studied and of the optimized 4‐21G geometries of cyclopropane, cyclobutane, cyclohexane, and bicyclo (2.1.0)pentane. Cooperative effects in the strain energies are discussed.

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