This program calculates 3JHH values according to Haasnoot et al.. Since the equation depends on the relative orientation of the substituents a molecular model will be of help. Turn the model so that the proton on the near side is pointing up then use the schemes below to determine the numbering of the substituents (e.g. S1, S2 etc.) and select the appropriate elements from the menus.
The program will automatically select to correct equation (C, D, or E) depending on the number of attached hydrogens.

Problems using this calculator? Write to roland.stenutz@organ.su.se and state the type of problem, the URL of this page and what browser you are using.

"The relationship between proton-proton nmr coupling constants and substituent electronegativities-I"
C.A.G. Haasnoot, F.A.A.M. DeLeeuw and C. Altona
Tetrahedron 36 (1980) 2783-2792


S1 S2 S3 S4
H/H torsion angle 3JHH