Synthesis of substituted picenes through Pd-catalyzed cross-coupling reaction/annulation sequences and their physicochemical properties.

A novel and versatile synthetic method for picene derivatives is developed using the Pd-catalyzed intramolecular double cyclization of the corresponding 2,3-bis[(1Z)-2-phenylethenyl]-1,4-dichlorobenzenes, which are readily prepared by Suzuki-Miyaura cross-coupling reactions of polyhalobenzenes with (Z)-arylethenylboronates. The physical properties of the obtained picenes can be modified via introducing a variety of functional groups to the picene framework. All compounds are investigated by UV-vis and fluorescence spectroscopic measurements, CV, and DFT calculations as well as X-ray diffraction analysis.