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A detailed evaluation of the dependence of 3 J (HH) on bond angle in alkenes and cycloalkenes
Author(s) -
Cooper M. Ashley,
Manatt Stanley L.
Publication year - 1970
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.1270020508
Subject(s) - coupling constant , proton , chemistry , spin (aerodynamics) , coupling (piping) , molecular geometry , computational chemistry , double bond , proton spin crisis , bond length , crystallography , physics , thermodynamics , molecule , materials science , nuclear physics , particle physics , organic chemistry , crystal structure , metallurgy
Newly determined and accurate data for the magnitudes of cis vinyl proton‐proton spin‐spin coupling constants in cis ‐dialkylethylenes and cycloalkenes have been obtained. With these new data and also values taken from the recent literature, it has proved possible to make a critical determination of the correlation between 3 J (HH) and CCH bond angles in ethylenic systems. It is suggested that it is possible to obtain accurate estimates of bond angles using NMR coupling constants, even though much more data will be required to fully substantiate this proposal. Whereas cis ‐ 3 J (HH) decreases rapidly with increasing CCH bond angles, evidence is presented that the opposite is the case for trans ‐ 3 J (HH). A brief theoretical discussion of these trends in coupling constants is given.