SYNTHESIS AND HIGH FIELD **1**3C-NMR SPECTRA OF ISOMERIC DIBENZYLBENZENES.

Structural characterization of polybenzyls is an important but difficult task, paricularly due to the complexity of polysubstitution which internal phenyl groups undergo during polymerization. In an earlier article, the authors reported the use of **1**3C-NMR spectroscopy to establish the presence of monosubstituted phenyls as well as some structural isomers of di-, tri-, and tetrasubstituted phenyls in the polybenzyl polymers. Since the **1**3C chemical shifts of these isomeric units are now known, they were theoretically calculated and their presence or absence in the observed spectrum was noted. In the reported experiments, the authors synthesized the ortho, meta, and para isomers of dibenzylbenzene and measured their **1**3C-NMR chemical shifts. The experimental values are found to be similar to the calculated values. An improved procedure for synthesis of the three structural isomers of dibenzylbenzenes is also reported.