Persistent Ambipolar Heptacenes and Their Redox Species.

Sixfold TIPS‐ethynylation combined with fourfold bromination of the armchair edges furnishes a long‐lived, soluble heptacene; π‐extension via Stille coupling accesses a persistent tetrabenzononacene. Both types of acenes were stabilized best by double TIPS‐ethynylation on every other benzene ring. Tetrabromoheptacene is an ambipolar transistor material (up to 0.036 cm2 V−1 s−1 n‐channel), which was corroborated by generation of its monoanion and monocation. [ABSTRACT FROM AUTHOR]