Shoolery'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

$\delta =0.23\mathrm{p}\mathrm{p}\mathrm{m}+S_{\mathrm{A}}+S_{\mathrm{B}}$

where 0.23 ppm is the chemical shift of methane and the empirical adjustments Template:Var 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 $S_B$.

External links

• Organic Spectroscopy: Principles and Applications, page 206

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