Symbiotic Control in Mechanical Bond Formation.
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 (BIPY(2+) ) 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 Cu(I) , 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.
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Yuping
Y
Wang
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Junling
J
Sun
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Zhichang
0000-0003-3412-512X
Z
Liu
Joint Center of Excellence in Integrated Nano-Systems (JCIN), King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh, 11442, KSA.
Majed S
MS
Nassar
PanaceaNano, Inc., 2265 East Foothill Boulevard, Pasadena, CA, 91107, USA.
Youssry Y
YY
Botros
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA. Stoddart@northwestern.edu.
J Fraser
0000-0003-3161-3697
JF
Stoddart
catenanes; click chemistry; radicals; rotaxanes; template-directed synthesis