Polyaryl anion radicals via alkali metal reduction of arylurea oligomers.

A series of N-methylated polyarylurea oligomers have been reduced with potassium metal in HMPA. These reductions result in the transient formation of arylurea anion radicals, which undergo reductive elimination of the urea linkages. The aryl moieties appear in the products as the anion radicals of oligoaryl systems. The reaction is intramolecular, and the sequencing in the polyaryl anion radical remains the same as in the polyarylureas due to the urea-enforced pi-pi stacking interactions.