Vinylic ( 3JHH ) and Allylic ( 4JHH ) Spin-Spin Coupling Estimation:

Type: Vinyl: C=CH-CH Allyl: HC=C-CH

Enter a value for phi or JHH and then click on the background:
phi: o  => JHH: +- 0.3 Hz

JHH: Hz  =>  phi:       +-15o

Equations and References

Colby NMR Home Page
Colby Chemistry Home Page

Colby College Chemistry, T. W. Shattuck, 1/10/2009