Electrochemically addressable trisradical rotaxanes organized within a metal-organic framework

Paul R McGonigal, Pravas Deria, Idan Hod, Peyman Z Moghadam, Alyssa-Jennifer Avestro, Noah E Horwitz, Ian C Gibbs-Hall, Anthea K Blackburn, Dongyang Chen, Youssry Y Botros, Michael R Wasielewski, Randall Q Snurr, Joseph T Hupp, Omar K Farha, J Fraser Stoddart

Research output: Contribution to journalArticlepeer-review


The organization of trisradical rotaxanes within the channels of a Zr6-based metal-organic framework (NU-1000) has been achieved postsynthetically by solvent-assisted ligand incorporation. Robust Zr(IV)-carboxylate bonds are forged between the Zr clusters of NU-1000 and carboxylic acid groups of rotaxane precursors (semirotaxanes) as part of this building block replacement strategy. Ultraviolet-visible-near-infrared (UV-Vis-NIR), electron paramagnetic resonance (EPR), and 1H nuclear magnetic resonance (NMR) spectroscopies all confirm the capture of redox-active rotaxanes within the mesoscale hexagonal channels of NU-1000. Cyclic voltammetry measurements performed on electroactive thin films of the resulting material indicate that redox-active viologen subunits located on the rotaxane components can be accessed electrochemically in the solid state. In contradistinction to previous methods, this strategy for the incorporation of mechanically interlocked molecules within porous materials circumvents the need for de novo synthesis of a metal-organic framework, making it a particularly convenient approach for the design and creation of solid-state molecular switches and machines. The results presented here provide proof-of-concept for the application of postsynthetic transformations in the integration of dynamic molecular machines with robust porous frameworks.

Original languageEnglish
Pages (from-to)11161-11168
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number36
Early online date17 Aug 2015
Publication statusPublished - 8 Sept 2015

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