Mixed-Valence Superstructure Assembled from a Mixed-Valence Host-Guest Complex

J Am Chem Soc. 2018 Aug 1;140(30):9387-9391. doi: 10.1021/jacs.8b05322. Epub 2018 Jul 17.

Abstract

Herein, we report an unprecedented mixed-valence crystal superstructure that consists of a 2:1 host-guest complex [MV⊂(CBPQT)2]2/3+ [MV = methyl viologen, CBPQT = cyclobis(paraquat- p-phenylene)]. One electron is distributed statistically between three [MV⊂(CBPQT)2]•+ composed of a total of 15 viologen units. The mixed-valence state is validated by single-crystal X-ray crystallography, which supports an empirical formula of [MV⊂(CBPQT)2]3·(PF6)2 for the body-centered cubic superstructure. Electron paramagnetic resonance provides further evidence of electron delocalization. Quantum chemistry calculations confirm the mixed-valence state in the crystal superstructure. Our findings demonstrate that precise tuning of the redox states in host-guest systems can lead to a promising supramolecular strategy for achieving long-range electron delocalization in solid-state devices.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't