Solid-state characterization and photoinduced intramolecular electron transfer in a nanoconfined octacationic homo[2]catenane

Jonathan C. Barnes, Marco Frasconi, Ryan M. Young, Nezar H. Khdary, Wei Guang Liu, Scott M. Dyar, Paul R. McGonigal, Ian C. Gibbs-Hall, Christian S. Diercks, Amy A. Sarjeant, Charlotte L. Stern, William A. Goddard, Michael R. Wasielewski, J. Fraser Stoddart*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


An octacationic homo[2]catenane comprised of two mechanically interlocked cyclobis(paraquat-p-phenylene) rings has been obtained from the oxidation of the septacationic monoradical with nitrosonium hexafluoroantimonate. The nanoconfinement of normally repulsive bipyridinium units results in the enforced π-overlap of eight positively charged pyridinium rings in a volume of <1.25 nm3. In the solid state, the torsional angles around the C-C bonds between the four pairs of pyridinium rings range between 16 and 30°, while the π-π stacking distances between the bipyridinium units are extended for the inside pair and contracted for the pairs on the outside-a consequence of Coulombic repulsion between the inner bipyridinium subunits. In solution, irradiation of the [2]catenane at 275 nm results in electron transfer from one of the paraphenylene rings to the inner bipyridinium dimer, leading to the generation of a temporary mixed-valence state within the rigid and robust homo[2]catenane.

Original languageEnglish
Pages (from-to)10569-10572
Number of pages4
JournalJournal of the American Chemical Society
Issue number30
Publication statusPublished - 30 Jul 2014

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