Synthesis, Structure, and Properties of Tetrabenzo7circulene

Tetrabenzo7circulene, a new member of aromatic saddles, was conveniently synthesized from 2-(1-naphthoyl)benzoic acid with the seven-membered ring constructed at an early stage of the synthesis. This method, upon minor modification, was also useful for synthesis of thiophene-annulated 7circulenes. The structures of tetrabenzo7circulene and 7circulene were compared in terms of symmetry, flexibility, and curvature on the basis of DFT calculations and X-ray crystallography. It was also found that tetrabenzo7circulene functioned as a p-type semiconductor in thin-film transistors and cocrystallized with C60.