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

where 0.23 ppm is the chemical shift of methane and the empirical adjustments S 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

,

with two substituents on methylene resulting in two parameters and .[1]

References

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