Characterization of aromatic polymers (benzenoid and heterocyclic) by cross‐polarization, magic‐angle 13C‐NMR spectroscopy

The cross‐polarization, magic‐angle 13C‐NMR spectra of solid samples of poly(p‐phenylene), its nitro derivative, polymerized biphenyl, poly(p‐phenylene sulfide), poly(1‐methyl‐2,5‐pyrrolylene), poly(1‐phenyl‐2,5‐pyrrolylene), poly(2,5‐thienylene), and poly(2,5‐selenienylene) and the high‐resolution 13C‐NMR spectrum of poly(m‐phenylene) in solution are presented and assigned. In all cases the chemical shifts are similar to those of model compounds in solution. In most instances the resonances of the nonprotonated carbon atoms in the solid polymers are more intense than those of the protonated carbons and appear to depend on the charge distribution in the molecular orbitals.