An equation utilizing empirically derived substituent constants for the prediction of vicinal coupling constants in substituted ethanes
✍ Scribed by William J. Colucci; Steven J. Jungk; Richard D. Gandour
- Publisher
- John Wiley and Sons
- Year
- 1985
- Tongue
- English
- Weight
- 823 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0749-1581
No coin nor oath required. For personal study only.
✦ Synopsis
A simple equation has been developed for the prediction of vicinal coupling constants in HCCH fragmentx
The equation is a cosine series in 8, the torsion angle between vicinal hydrogens. The feature which distinguishes this equation from similar equations is the inclusion of ASi terms, which describe the magnitude of each substituent's effect. These substituent constants have been defined from experimental data. An orientation effect which is dependent on the torsion angle(s) between substituent(s) and a vicinal hydrogen is included. Substituent constants have been defined for 39 groups, of which 15 have been experimentally determined herein. The parameters for the equation have been defined from 49 torsion angles in 19 conformationally rigid compounds. The torsion angles have been determined from x-ray crystal structure data and molecular mechanics calculations. The multiplicity of structures used to determine the substituent constants should allow for the application of this equation to a wide variety of structures.