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. . . pi] interactions although there are no p-p 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 cm(2) V-1 s(-1). Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm(2) V-1 s(-1).