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The role of linear electric field effects in halogen induced 13 C chemical shifts in cyclohexanes and methylenecyclohexanes
Author(s) -
Van Dommelen Marianne E.,
de Haan Jan W.,
Buck Henk M.
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270130611
Subject(s) - cyclohexanes , chemistry , chemical shift , double bond , halogen , computational chemistry , stereochemistry , organic chemistry , alkyl
The 13 C NMR chemical shifts of methylenecyclohexane at low temperature are compared with those of 4‐chloro‐ and 4‐bromo‐methylenecyclohexane under the same conditions. It is concluded that the halogen induced shift differences at the double bond are to be ascribed largely to linear electric field (LEF) effects. At the same time, doubt is expressed concerning similar explanations for C‐4 in halo‐substituted cyclohexanes. The large influence of using different values of longitudinal bond polarizabilities is demonstrated. Finally, some remarkable long‐range shift effects on double bonds are described for geranyl chloride and geranyl bromide.