Air- and Heat-Stable Planar Tri-p-quinodimethane with Distinct Biradical Characteristics.

A heptacyclic carbocyde possessing three p- quinodimethane units conjugated in one plane has been synthesized and shown to exhibit distinct biradical character- istics. The molecule has a HOMO/LUMO band gap of ca. 1 eV and a S0-T1 energy gap of 2.12 kcal/mol, and it absorbs and exriits near-IR light at room temperature. It is air-stable under ambient light for several months and thermally stable up to 160 °C under nitrogen, and it undergoes reversible two-electron oxidation and reduction. The synthetic approach is such that a smaller and larger oligo-p-quinodimethane can be synthesized. [ABSTRACT FROM AUTHOR]