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Abstract Low‐strain cyclic olefin monomers, including five‐membered, six‐membered, eight‐membered, and macrocyclic rings, have been recently exploited for the synthesis of depolymerizable polyolefins via ring‐opening metathesis polymerization (ROMP). Such polyolefins can undergo ring‐closing metathesis depolymerization (RCMD) to regenerate their original monomers. Nevertheless, the depolymerization behavior of polyolefins prepared by ROMP of seven‐membered cyclic olefins, an important class of low‐strain rings, still remains unexplored. In this study, we demonstrate the chemical recycling of polyheptenamers to cycloheptene under standard RCMD conditions. Highly efficient depolymerization of polyheptenamer was enabled by Grubbs' second‐generation catalyst in toluene. It was observed that the monomer yields increased when the depolymerization temperature increased and the starting polymer concentration was reduced. A near‐quantitative monomer regeneration (>96%) was achieved within 1 h under dilute conditions (20 mM of olefins) at 60°C. Moreover, polyheptenamer exhibited a decomposition temperature above 430°C, highlighting its potential as a new class of thermally stable and chemically recyclable polymer materials.
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This content will become publicly available on May 20, 2026
Metathesis Depolymerization of a Fluorogenic Self-Immolative Polymer
We report a self-immolative polymer (SIP) that generates a fluorescent response upon metathesis depolymerization. Functionally distinct from other degradable polymers, SIPs offer the ability to release many subunits per one signal molecule, making them advantageous for a variety of applications such as molecular detection and signal amplification. Utilizing robust copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) chemistry to orthogonally functionalize alkynes, fluorophore coumarin and quencher 4-((4-(dimethylamino)phenyl)azo) (DABCYL) were efficiently installed as side chains on the SIP. The depolymerization mediated by Grubbs 3rd-generation (G3) organoruthenium initiator enabled a fluorescence turn-on response under nanomolar SIP concentrations. To demonstrate the utility of the fluorogenic SIP, we showed a temperature-dependent fluorescence turn-on of this metathesis-triggered SIP using a thermally responsive Grubbs 2nd-generation (G2) organoruthenium initiator.
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- Award ID(s):
- 1944512
- PAR ID:
- 10594476
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- ACS Macro Letters
- Volume:
- 14
- Issue:
- 5
- ISSN:
- 2161-1653
- Page Range / eLocation ID:
- 558 to 563
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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