Cooperative Self‐Assembly of Pyridine‐2,6‐Diimine‐Linked Macrocycles into Mechanically Robust Nanotubes
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- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Polymer Science The University of Akron Akron OH 44325 USA
- Department of Chemistry Northwestern University 2145 Sheridan Road Evanston IL 60208 USA, Department of Chemistry and Chemical Biology, Baker Laboratory Cornell University Ithaca NY 14853 USA
Abstract Nanotubes assembled from macrocyclic precursors offer a unique combination of low dimensionality, structural rigidity, and distinct interior and exterior microenvironments. Usually the weak stacking energies of macrocycles limit the length and mechanical strength of the resultant nanotubes. Imine‐linked macrocycles were recently found to assemble into high‐aspect ratio (>10 3 ), lyotropic nanotubes in the presence of excess acid. Yet these harsh conditions are incompatible with many functional groups and processing methods, and lower acid loadings instead catalyze macrocycle degradation. Here we report pyridine‐2,6‐diimine‐linked macrocycles that assemble into high‐aspect ratio nanotubes in the presence of less than 1 equiv of CF 3 CO 2 H per macrocycle. Analysis by gel permeation chromatography and fluorescence spectroscopy revealed a cooperative self‐assembly mechanism. The low acid concentrations needed to induce assembly enabled nanofibers to be obtained by touch‐spinning, which exhibit higher Young's moduli (1.33 GPa) than many synthetic polymers and biological filaments. These findings represent a breakthrough in the design of inverse chromonic liquid crystals, as assembly under such mild conditions will enable the design of structurally diverse and mechanically robust nanotubes from synthetically accessible macrocycles.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- DGE-1324585
- OSTI ID:
- 1562125
- Journal Information:
- Angewandte Chemie, Journal Name: Angewandte Chemie Vol. 131 Journal Issue: 41; ISSN 0044-8249
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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