P. Hansen, J. J. Led
Mar 1, 1981
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Journal
Magnetic Resonance in Chemistry
Abstract
1H, 2H and 13C NMR studies of cyclobutene and a series of isotopically enriched species have led to a determination of the 1H1H, 13C1H, 13C2H and 13C13C coupling constants in these compounds. In agreement with general observations, 1J(CH) is found to depend on the hybridization of the carbon atoms. Likewise, 2J(HH), 2J(CC), 3J(HH) and 3J(CH), but not 2J(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 1J(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.