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Nichtplanare Doppelbindung in einem kristallinen Derivat von anti ‐Sesquinorbornen ( anti ‐Tetracyclo[6.2.1.1 3,6 .0 2,7 ]dodec‐2(7)‐en)
Author(s) -
Ermer Otto,
Bödecker ClausDieter
Publication year - 1983
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19830660328
Subject(s) - chemistry , stereochemistry
Non‐Planar Double Bond in a Crystalline Derivative of anti ‐Sesquinorbornene ( anti ‐Tetracyclo[6.2.1.1 3,6 .0 2,7 ]dodec‐2(7)‐ene) The olefinic double bond of the title compound 2 has been observed by X‐ray techniques to deviate from planarity by 13.2 (0.3)° (symmetric out‐of‐plane bending). Empirical force field calculations for the parent hydrocarbon 1 ( anti ‐sesquinorbornene) give a much larger corresponding deviation of 35.6°. The calculated nonplanar double bond deformations in anti ‐sesquinorbornene 1 as well as in the syn ‐isomer 4 and other related olefins are a consequence of substantial widenings of the exocyclic C(sp 3 )–C(sp 2 –Csp 3 ) angles when keeping the double bond planar. The considerable computational exaggeration of this novel out‐of‐plane bending mechanism is attributed to various possible force field deficiencies.