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Carbon‐13 nuclear magnetic resonance spectroscopy IX—monosubstituted ethylenes
Author(s) -
Miyajima Goh,
Takahashi Kensuke,
Nishimoto Kichisuke
Publication year - 1974
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.1270060803
Subject(s) - chemical shift , chemistry , substituent , benzene , carbon fibers , ethylene , coupling constant , carbon 13 , computational chemistry , organic chemistry , materials science , physics , particle physics , quantum mechanics , composite number , composite material , catalysis
Carbon‐13 chemical shifts of sixteen monosubstituted ethylenes were obtained. In order to explain the chemical shifts, σ and π electron densities of these compounds are calculated by the σ‐included ω‐HMO method. See Ref. 8. A linear relationship exists between carbon‐13 chemical shifts and the calculated electron densities, and also between substituent constants and electron densities. A slope of unity is obtained between the chemical shifts of α carbons of monosubstituted ethylenes and those of carbons adjacent to the substituents in monosubstituted benzenes. On the other hand, a plot of chemical shifts of C ortho of benzene derivatives against that of the β carbon in ethylene derivatives gives a slope of 3. These slopes can be explained by the calculated electron densities. A slope of 4/3 is obtained between the direct coupling constant 1 J (CH) of the α carbon in monosubstituted ethylenes and that in the corresponding substituted methanes.