Benzoannelated (2.2)paracyclophanes: synthesis and electronic properties

The synthesis of benzoannelated (2.2)paracyclophanes leads to a study of their electronic properties. The process involves the series alkenylation of vicinal di- and tetrabromoalkanes with subsequent cyclization and dehydrogenation of the resulting (E,Z,E)-trienes. Spectroscopic and cyclic voltammetric studies show that, while the cyclophanes' pi-subsystems are too far for stepwise reduction, they can interact well enough with one another. This makes the cyclophanes highly efficient acceptors of four to six electrons.