Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents

Alvaradejo, Gabriela Gil; Nguyen, Hung V.-T.; Harvey, Peter; Gallagher, Nolan M.; Le, Dao; Ottaviani, M. Francesca; Jasanoff, Alan; Delaittre, Guillaume; Johnson, Jeremiah A.

Abstract

Copyright © 2019 American Chemical Society. The synthesis of functional poly(2-alkyl-2-oxazoline) (PAOx) copolymers with complex nanoarchitectures using a graft-through ring-opening metathesis polymerization (ROMP) approach is described. First, well-defined norbornene-terminated poly(2-ethyl-2-oxazoline) (PEtOx) macromonomers (MM) were prepared by cationic ring-opening polymerization. ROMP of these MMs produced bottlebrush copolymers with PEtOx side chains. In addition, PEtOx-based branched MMs bearing a terminal alkyne group were prepared and conjugated to an azide-containing bis-spirocyclohexyl nitroxide via Cu-catalyzed azide-alkyne cycloaddition (CuAAC). ROMP of this branched MM, followed by in situ cross-linking, provided PEtOx-based brush-arm star polymers (BASPs) with nitroxide radicals localized at the core-shell interface. These PEtOx-based nitroxide-containing BASPs displayed relaxivity values on par with state-of-the-art polyethylene glycol (PEG)-based nitroxide materials, making them promising as organic radical contrast agents for metal-free magnetic resonance imaging (MRI).

Citation

Alvaradejo, G. G., Nguyen, H. V.-T., Harvey, P., Gallagher, N. M., Le, D., Ottaviani, M. F., Jasanoff, A., Delaittre, G., & Johnson, J. A. (2019). Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents. ACS Macro Letters, 8(4), 473-478. https://doi.org/10.1021/acsmacrolett.9b00016

• Journal Article Type: Article
• Acceptance Date: Mar 11, 2019
• Online Publication Date: Apr 4, 2019
• Publication Date: Apr 16, 2019
• Deposit Date: Oct 23, 2019
• Publicly Available Date: Apr 5, 2020
• Journal: ACS Macro Letters
• Electronic ISSN: 2161-1653
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 4
• Pages: 473-478
• DOI: https://doi.org/10.1021/acsmacrolett.9b00016
• Public URL: https://nottingham-repository.worktribe.com/output/2828753
• Publisher URL: https://pubs.acs.org/doi/10.1021/acsmacrolett.9b00016
• Additional Information: This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Macro Letters, copyright © American Chemical Society after peer review. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsmacrolett.9b00016.
• Contract Date: Oct 23, 2019