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Updated: Jun 8, 2026

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry
Published on: August 25, 2016
Using the rotaxane mechanical bond to enhance chemical reactivity
Jeffrey M Baumes1, Ivan Murgu, Allen Oliver
1Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Abstract:
Rates of cycloreversion for squaraine rotaxane mono(endoperoxides) were enhanced by structural modifications that increased cross-component steric destabilization of the inward directed 9,10-anthracene endoperoxide group. The largest rate enhancements were obtained when the surrounding macrocycle contained two 2,6-pyridine dicarboxamide bridging units, which induced a cavity contraction effect. The precursor fluorescent, near-IR, squaraine rotaxanes are effectively photostable because the mono(endoperoxide) products, formed by reaction with photogenerated singlet oxygen, rapidly cyclorevert back to the original squaraine rotaxane.
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