Carbon-13 nuclear magnetic resonance spectroscopy IX—monosubstituted ethylenes

✍ Scribed by Goh Miyajima; Kensuke Takahashi; Kichisuke Nishimoto

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: English
• Weight: 497 KB
• Volume: 6
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270060803

✦ Synopsis

Abstract

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(CH) of the α carbon in monosubstituted ethylenes and that in the corresponding substituted methanes.