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Published May 6, 2008 | Supplemental Material + Published
Journal Article Open

Folding of a donor–acceptor polyrotaxane by using noncovalent bonding interactions


Mechanically interlocked compounds, such as bistable catenanes and bistable rotaxanes, have been used to bring about actuation in nanoelectromechanical systems (NEMS) and molecular electronic devices (MEDs). The elaboration of the structural features of such rotaxanes into macromolecular materials might allow the utilization of molecular motion to impact their bulk properties. We report here the synthesis and characterization of polymers that contain π electron-donating 1,5-dioxynaphthalene (DNP) units encircled by cyclobis(paraquat-p-phenylene) (CBPQT4+), a π electron-accepting tetracationic cyclophane, synthesized by using the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The polyrotaxanes adopt a well defined "folded" secondary structure by virtue of the judicious design of two DNP-containing monomers with different binding affinities for CBPQT4+. This efficient approach to the preparation of polyrotaxanes, taken alongside the initial investigations of their chemical properties, sets the stage for the preparation of a previously undescribed class of macromolecular architectures.

Additional Information

© 2008 by the National Academy of Sciences. Edited by Jack Halpern, University of Chicago, Chicago, IL, and approved February 26, 2008 (received for review November 21, 2007). Published online before print April 30, 2008, doi: 10.1073/pnas.0711072105. Generous financial support by the Semiconductor Research Corporation through its focus centers of Functional Engineered NanoArchitectonics and Materials, Structures, and Devices in addition to the MolApps Program funded by the Defense Advanced Research Projects Agency is acknowledged gratefully. Author contributions: W.Z., W.R.D., A.Z.S., D.B., J.K.G., J.R.H., and J.F.S. designed research; W.Z., W.R.D., A.Z.S., and D.B. performed research; and W.Z., W.R.D., A.Z.S., D.B., J.K.G., J.R.H., and J.F.S. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/cgi/content/full/0711072105/DCSupplemental.

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Published - ZHApnas08a.pdf

Supplemental Material - 0711072105SI.pdf


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