Long-Range proton-proton coupling constants. I. Propanic coupling involving a methyl group 4JMeH

✍ Scribed by Angel L. Esteban; Maria P. Galache; Francisco Mora; Ernesto Diez; Jesus San Fabian

• Book ID: 102878397
• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 734 KB
• Volume: 10
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.540100705

✦ Synopsis

An equation is formulated on the basis of theoretical INDOIFPI' calculations which describes the angular dependence of the propanic long-range coupling constant 4 J ~, H in substituted HCCCH, fragments.

This equation is a truncated Fourier series in the torsion angle 6, HCCMe, which takes into account the dependence of the Fourier coefficients on the bond angle 6, CCMe. The substituent effects are assumed to be additive. Some parameters in the equation may be obtained from the 4JM,H couplings in propane and neopentane derivatives. The calculated effect upon 4 J ~, ~ of changes in the bond angle 6 is significant and it seems to be in part the cause of some effects which have been attributed to conformational dependence.