Linear and star-shaped pyrazine-containing acene dicarboximides with high electron-affinity

A series of linear and star-shaped pyrazine-containing acene molecules 1a-b, 2a-b and 3 substituted by dicarboximide groups are synthesized via condensation reactions between o-diamine and dione. High electron affinity (up to 4.01 eV) is achieved due to the introduction of an electron-deficient pyrazine moiety and the attachment of electron-withdrawing dicarboximide groups. Some of these molecules show thermal liquid crystalline behavior and their space-charge limited current mobilities are measured. The high electron affinity and liquid crystalline property qualify them as promising electron transporting materials in organic optoelectronic devices.