1. Symbiotic Control in Mechanical Bond Formation.
- Author
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Wang, Yuping, Sun, Junling, Liu, Zhichang, Nassar, Majed S., Botros, Youssry Y., and Stoddart, J. Fraser
- Subjects
BOND formation mechanism ,GEMINATE pairs (Molecules) ,CATENANES ,ROTAXANES ,RADICAL cations ,MOLECULAR machinery (Technology) - Abstract
Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY
.+ units, the radical cationic state of 4,4′-bipyridinium (BIPY2+ ) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY.+ radical cations, while the metal itself, which is oxidized to CuI , catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY.+ radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium. [ABSTRACT FROM AUTHOR]- Published
- 2016
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