NMR8. Chemical Shift in 1H NMR
- Page ID
- 4199
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The trends here are exactly the same as in carbon spectra. Wherever the carbon goes, it takes the proton with it. By analogy with carbon spectra,
Source: Simulated spectrum.
Figure NMR12.1H NMR spectrum of 1-hexene.
Source: Simulated spectrum.
Figure NMR13.1H NMR spectrum of butanal.
Source: Simulated spectrum.
As before, there are also hydrogens on linear carbons, although they are much less common than tetrahedral or trigonal carbons.
- Remember, these are general rules that you should know. There will occasionally be exceptions; the proton in a carboxylic acid may be seen at 12 ppm, and the proton in chloroform shows up at 7 ppm although it is attached to a tetrahedral carbon. (World-record shifts occur for hydrogens attached to transition metals: "late" metals like ruthenium or rhodium can move hydrogen peaks all the way up to -20 ppm, but "early" metals like tantalum can move them down as far as 25 ppm.)
Contributors and Attributions
- Remember, these are general rules that you should know. There will occasionally be exceptions; the proton in a carboxylic acid may be seen at 12 ppm, and the proton in chloroform shows up at 7 ppm although it is attached to a tetrahedral carbon. (World-record shifts occur for hydrogens attached to transition metals: "late" metals like ruthenium or rhodium can move hydrogen peaks all the way up to -20 ppm, but "early" metals like tantalum can move them down as far as 25 ppm.)