Physics:Shoolery's rule
From HandWiki
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
- [math]\displaystyle{ \delta = 0.23\,\mathrm{ppm} + S_\mathrm{A} + S_\mathrm{B} }[/math]
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 |
External links
Original source: https://en.wikipedia.org/wiki/Shoolery's rule.
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