Synthesis and characterization of planar five-ring-fused dithiophene-dione

Article abstract of DOI:10.1002/cjoc.201100141

A series of new organic semiconductors based on s-indaceno[1,2-b:5,6- b′]dithiophene-4,9-dione was successfully synthesized and characterized. The electron withdrawing carbonyl group lowers the LUMO energy levels, leading to increased electronegativities, which is beneficial for high photo-stability in air. The n-alkyl substituted compounds, 1c and 1d, crystallize with the rigid coplanar systems packed into slipped face-to-face π-stacks. Interestingly, 1c and 1d also show liquid crystalline behaviors, which give highly ordered molecular packing over large area.