Regions of the proton NMR spectrum

All the H atoms in the last example were attached to sp carbons, so you will expect them to fall between 0 and 5 ppm. However, you can clearly see that H atoms that are nearer to oxygen are shifted downfield within the 0-5 ppm region, to larger 6 values (here as far as 3.3 and 3.9 ppm). We can use this fact to buUd some more detail into our picture of the regions of the NMR spectrum. 

In this chapter you will see a lot of numbers—chemical shifts and differences in chemical shifts. We need these to show that the ideas behind NMR are securely based in fact. You do not need to learn these numbers. Comprehensive tables can be found at the end of Chapter 18, which we hope you will find useful for reference while you are solving problems. 

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The integration gives useful—indeed essential—information, but it is much more important to understand the reasons for the exact chemical shift of the different types of proton. In the last example you can see one marked similarity to carbon spectra protons on saturated carbon atoms next to oxygen are shifted downfield to larger 5 values (here 3.3 and 3.9 p.p.m.). The other regions of the proton NMR spectrum are also quite similar in general outline to those of 13C spectra. Here they are. 

Thus, to give but one example (Figure 15), the aromatic region of the proton NMR spectrum of benzyl alcohol is... 

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