Pentagon-Containing π-Expanded Systems: Synthesis and Photophysical Properties.

We have designed and synthesized three novel twistacene-modified enlarged pentagon-containing π-systems (6 and 9) with mismatched structures. The introduction of electron-withdrawing cyclopenta rings in the parent skeleton effectively stabilizes the electron-rich arenes. Their optoelectronic properties were studied via ultraviolet-visible (UV-vis) absorption spectra, fluorescence spectra, cyclic voltammetry, and density functional theory (DFT) calculation. In addition, chemical oxidation of the as-prepared compounds with nitrosonium hexafluoroantimonate could form the corresponding cationic radicals.