New Heteroacenes For Organic Electronics

Conducting materials in organic light-emitting diodes (OLEDs), solar cells, and other devices often depend on conjugated heterocyclic ring systems for optical, electronic, and redox functions. Chemists are forever designing new versions of the molecules to tweak their properties for a variety of applications. Two research teams now report additions to the molecular collection. Hans-Ulrich Reissig and coworkers of the Free University of Berlin created a set of thiophene-substituted pyridines. The compounds include the first fully substituted thienylpyridine (shown) and dimeric versions separated by a bridging thiophene or alkyne group. The syntheses demonstrate the power of palladium-catalyzed cross-coupling reactions, the researchers say, as the reactions proceed well even in the sterically highly encumbered systems (Org. Lett., DOI: 10.1021/ol303231c). Separately, a team led by Régis Réau and Muriel Hissler of CNRS-University of Rennes 1, in France, and Zheng Duan of Zhengzhou University, in China, created the first phosphole compounds fused with flanking benzofuran groups. When incorporated in an OLED, the version shown emits blue-green light with good thermal stability (Org. Lett., DOI: 10.1021/ol303260d).