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CH, CD, CC and HH coupling constants in isotopically enriched cyclobutene
Author(s) -
Hansen Poul Erik,
Led Jens J.
Publication year - 1981
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.1270150316
Subject(s) - cyclobutene , coupling constant , chemistry , deuterium , kinetic isotope effect , isotope , carbon 13 , chemical shift , computational chemistry , crystallography , atomic physics , ring (chemistry) , physics , organic chemistry , nuclear physics , particle physics
1 H, 2 H and 13 C NMR studies of cyclobutene and a series of isotopically enriched species have led to a determination of the 1 H 1 H, 13 C 1 H, 13 C 2 H and 13 C 13 C coupling constants in these compounds. In agreement with general observations, 1 J (CH) is found to depend on the hybridization of the carbon atoms. Likewise, 2 J (HH), 2 J (CC), 3 J (HH) and 3 J (CH), but not 2 J (CH), depend on the angles between the bonds connecting the coupled nuclei. When comparing cyclobutene with thiete 1,1‐dioxide (thiete sulphone) an increase of almost 20 Hz is observed for 1 J (C‐2, H‐2) in the latter compound. All but one of the observed deuterium isotope effects on chemical shifts are negative. In the case of isotope effects upon the one‐bond coupling constants, the obtained values support the results of the theoretical calculations of Sergeev and Solkan.