Poly[n]catenanes Synthesis of molecular interlocked chains

• Published in: Science (American Association for the Advancement of Science) Vol. 358; no. 6369; pp. 1434 - 1439
• Main Authors: Wu, Qiong, Rauscher, Phillip M., Lang, Xiaolong, Wojtecki, Rudy J., de Pablo, Juan J., Hore, Michael J. A., Rowan, Stuart J.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 15.12.2017; The American Association for the Advancement of Science; AAAS
• Subjects: Catalysis; Chemical bonds; Chemical synthesis; Glass transition temperature; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Macromolecules; Metathesis; Molecular chains; Molecular machines; NMR; Nuclear magnetic resonance; Polymers; Resonance scattering; Spacer; Spectrometry; Tethering; Topology; Transition temperatures; Zinc
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aap7675

As the macromolecular version of mechanically interlocked molecules, mechanically interlocked polymers are promising candidates for the creation of sophisticated molecular machines and smart soft materials. Poly[n]catenanes, where the molecular chains consist solely of interlocked macrocycles, contain one of the highest concentrations of topological bonds. We report, herein, a synthetic approach toward this distinctive polymer architecture in high yield (∼75%) via efficient ring closing of rationally designed metallosupramolecular polymers. Light-scattering, mass spectrometric, and nuclear magnetic resonance characterization of fractionated samples support assignment of the high–molar mass product (number-average molar mass ∼21.4 kilograms per mole) to a mixture of linear poly[7–26]catenanes, branched poly[13–130]catenanes, and cyclic poly[4–7]catenanes. Increased hydrodynamic radius (in solution) and glass transition temperature (in bulk materials) were observed upon metallation with Zn2+.