Aromatic NMR

α-chloro-p-xylene - Note the deshielded methyl group, from e^- donation into the ring

Aromatic protons: 6.5 - 8 ppm. These are easily identified since very few environments absorb in this region. A highly deshielded vinyl proton could be found here, but it is rare.

Benzylic protons: 2.3 - 2.7 ppm

The largest shifts are found when electron withdrawing groups such as NO₂ are attached, deshielding the protons in the ring. The reverse is true for electron-donating groups like MeO.

Aromatic protons experience coupling right across the ring, but the clear differences in J values often allow substitution patterns to be determined by measuring them - described in a future post.