Fully Conjugated [4]Chrysaorene. Redox-Coupled Anion Binding in a Tetraradicaloid Macrocycle

Gregolińska, H.; Majewski , M.A.; Chmielewski, P.J.; Gregoliński, J.; Chien, A.; Zhou, J.; Wu, Y.-L.; Bae, Y. J.; Wasielewski, M.R.; Zimmerman, P. M.; Stępień, M.
J. Am. Chem. Soc. 2018, 140, 14474–14480 | view at publisher's site

[4]Chrysaorene, a fully conjugated carbocyclic coronoid, is shown to be a low-bandgap π-conjugated system with a distinct open-shell charac-ter. The system shows good chemical stability and can be oxidized to well-defined radical cation and dication states. The cavity of [4]chrysaorene acts as an anion receptor towards halide ions with a particular selectivity toward iodides (Ka = 207 ± 6 M−1). The interplay be-tween anion binding and redox chemistry is demonstrated using a 1H NMR analysis in solution. In particular, a well resolved, paramagnetically shifted spectrum of the [4]chrysaorene radical cation is observed, providing evidence for the inner binding of the iodide. The radical cation–iodide adduct can be generated in thin solid films of [4] chrysaorene by simple exposure to diiodine vapor.