NMR Chemical
Shift Predictor
Estimate expected proton chemical shifts from functional groups, neighbors, and molecular environment. Deterministic rules — not AI.
Predictor Workspace
Select an environment — the range updates instantly.
Functional group
Proton on carbon bearing an OH (α to oxygen).
Neighboring atoms
Electronegative atoms nearby
Aromatic ring
Hydrogen bonding
Conjugation
–OR, –NR₂, alkyl
–NO₂, –CN, –COR
Exchangeable proton
Expected chemical shift
δ 3.5–4.2 ppm
Midpoint ≈ 3.84 ppm · Alcohol
The selected environment maps cleanly onto a well-tabulated ¹H chemical-shift region with limited conflicting modifiers.
Visualization
DeshieldingWhy this result
- 01The proton is in a alcohol environment. Textbook reference ranges place the characteristic proton(s) near δ 3.3–4.0 ppm.
- 02The proton is attached to (or near) carbon adjacent to oxygen. Oxygen withdraws electron density through the inductive effect. This deshields the proton, causing a downfield shift.
- 03Hydrogen bonding reduces electron density at the proton (especially OH/NH), shifting the signal downfield and often broadening it.
- 04Neighboring C withdraw electron density through the inductive effect, deshielding the observed proton.
- 05Weak H-bonding partially deshields the proton (especially exchangeable OH/NH).
- 06Typical adjusted range: δ 3.5–4.2 ppm.
Rule adjustments
Chemical shift scale
0 → 12 ppm · search or hover a region
Learn & compare
Concepts, side-by-side ranges, and the reference table
Shielding
Electron density around a nucleus reduces the effective magnetic field it feels.
- In NMR, nuclei are studied in a strong external magnetic field B₀.
- Surrounding electrons generate a small opposing field — this shields the nucleus.
- More shielding → resonance at lower frequency → smaller chemical shift (upfield, right on conventional plots).
- Alkyl protons far from electronegative atoms are relatively shielded (~0.8–1.5 ppm).
Frequently asked questions
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