Shoolery's rule explained

Shoolery's rule should not be confused with Shelley's rule.

Shoolery's rule, which is named after James Nelson Shoolery, is a good approximation of the chemical shift δ of methylene groups in proton nuclear magnetic resonance. We can calculate shift of the CH₂ protons in a A–CH₂–B structure using the formula

\delta = 0 . 23 ppm + S _{A} + S _{B} where 0.23 ppm is the chemical shift of methane and the empirical adjustments are based on the identities of the A and B groups:

Substituent	S / ppm
–CH3	0.47
–COOR	1.55
–COR	1.70
–C6H5	1.83
–SR	1.64
–I	1.82
–Br	2.33
–OR	2.36
–Cl	2.53
–OH	2.56
–OCOR	3.13

Shoolery's rule is a particular instance of a general class of rules of the form

\delta = b _{0} + \sum _{i} z _{i} ,with two substituents on methylene resulting in two parameters S _{A} and S _{B} .^[1]

External links

• Organic Spectroscopy: Principles and Applications, page 206

Notes and References

1. Schaller . Renate . Arnold . Cédric . Pretsch . Ernö . New parameters for predicting 1H NMR chemical shifts of protons attached to carbon atoms . Analytica Chimica Acta . 1995-08-18 . 312 . 1 . 95-105 . 10.1016/0003-2670(95)00106-A . 2024-02-06.