A perylene five-membered ring diimide PDI39 was developed as a new electron-deficient building block for n-type semiconductors. The π-expanded conjugated molecules entailing azulenes were synthesized from PDI39. These conjuagted molecules...

Non-benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi-[7]annulene core. Derivatives of this new non-benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels-Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6-triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non-benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new nonbenzenoid acene can be oxidized or reduced by NOSbF 6 or KC 8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic.