As the macromolecular version of mechanically interlocked molecules, mechanically interlocked polymers (MIPs) are intriguing candidates for creation of sophisticated molecular machines and smart soft materials. Poly[n]catenanes, where the molecular chains consist solely of interlocked macrocycles, are some of the most interesting types of MIPs, as they contain one of the highest concentrations of topological bonds. However, a confirmed synthesis of high molecular weight poly[n]catenanes has yet to be achieved. We report, herein, a synthetic approach toward this unique polymer architecture in high yield (~75%) via efficient ring-closing of rationally-designed metallosupramolecular polymers (MSPs). Through a combination of GPC-MALS, 1H NMR and MALDI-MS on fractionated samples, it is shown that the high molecular weight product (average Mn= 21.4 kDa) is a mixture of linear poly[7–26]catenanes, branched poly[13–130]catenanes and cyclic poly[4–7]catenanes. The metallo-responsive behavior of linear and branched poly[n]catenanes was also observed, as manifested by an increased hydrodynamic radius (Rh, in solution) and glass transition temperature (Tg, in bulk materials) upon metallation with Zn2+.

Poly[n]catenanes: The synthesis of molecular interlocked chains

255th National Meeting (2018)

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