Non-uniform Photoinduced Unfolding of Supramolecular Polymers Leading to Topological Block Nanofibers.

Tashiro, Keigo; Katayama, Kosuke; Tamaki, Kenta; Pesce, Luca; Shimizu, Nobutaka; Takagi, Hideaki; Haruki, Rie; Hollamby, Martin J.; Pavan, Giovanni M.; Yagai, Shiki

Abstract

Synthesis of one-dimensional nanofibers with distinct topological (higher-order structural) domains in the same main chain is one of the challenging topics in modern supramolecular polymer chemistry. Non-uniform structural transformation of supramolecular polymer chains by external stimuli may enable preparation of such nanofibers. To demonstrate feasibility of this post-polymerization strategy, we prepared a photoresponsive helically folded supramolecular polymers from a barbiturate monomer containing an azobenzene-embedded rigid pi-conjugated scaffold. In contrast to previous helically folded supramolecular polymers composed of a more flexible azobenzene monomer, UV-light induced unfolding of the newly prepared helically folded supramolecular polymers occurred nonuniformly, affording topological block copolymers consisting of folded and unfolded domains. The formation of such blocky copolymers indicates that the photoinduced unfolding of the helically folded structures initiates from relatively flexible parts such as termini or defects. Spontaneous refolding of the unfolded domains was observed after visible-light irradiation followed by aging to restore fully folded structures.

Citation

Tashiro, K., Katayama, K., Tamaki, K., Pesce, L., Shimizu, N., Takagi, H., Haruki, R., Hollamby, M. J., Pavan, G. M., & Yagai, S. (2021). Non-uniform Photoinduced Unfolding of Supramolecular Polymers Leading to Topological Block Nanofibers. Angewandte Chemie International Edition, 60(52), 26986-26993. https://doi.org/10.1002/anie.202110224

• Journal Article Type: Article
• Acceptance Date: Oct 5, 2021
• Online Publication Date: Oct 8, 2021
• Publication Date: Dec 20, 2021
• Journal: Angewandte Chemie International Edition
• Print ISSN: 1433-7851
• Electronic ISSN: 1521-3773
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 60
• Issue: 52
• Pages: 26986-26993
• DOI: https://doi.org/10.1002/anie.202110224
• Keywords: azobenzene; barbituric acid; co-polymer; supramolecular polymer; topological transition
• Public URL: https://keele-repository.worktribe.com/output/421319
• Publisher URL: https://onlinelibrary.wiley.com/doi/10.1002/anie.202110224