Dianthraceno[a,e]pentalenes: synthesis, crystallographic structures and applications in organic field-effect transistors†
Two soluble and stable dianthraceno[a,e]pentalenes with two (DAP1) and six (DAP2) phenyl substituents were synthesized. Both compounds possess a small energy band gap and show amphoteric redox behaviour due to intramolecular donor–accepter interactions. X-ray crystallographic analysis revealed that DAP2 has a closely packed structure with multi-dimensional [C–H⋯π] interactions although there are no π–π interactions between the dianthraceno[a,e]pentalene cores. As a result, solution-processed field effect transistors based on DAP2 exhibited an average hole mobility of 0.65 cm2 V−1 s−1. Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm2 V−1 s−1.