2013 (English)In: RSC Advances, ISSN 2046-2069, Vol. 3, no 7, 2341-2350 p.Article in journal (Refereed) Published
Three photothermal-responsive α-cyclodextrin-based rotaxanes were prepared via the copper(i)-catalyzed azide-alkyne cycloaddition, in which the α-cyclodextrin ring was threaded onto the azobenzene dumbbell component. The difference between the three rotaxanes are the length of the ethylene glycol repeating chains connected between the azobenzene and triazole units in the dumbbell components. The α-cyclodextrin rings in the rotaxanes can be reversibly switched between the azobenzene unit and triazole/ethylene glycol unit driven by the trans-cis isomerization of the azobenzene unit. The trans-to-cis isomerization of the azobenzene unit under UV light irradiation (365 nm) leads the α-cyclodextrin ring moving to the triazole/ethylene glycol unit, while the cis-to-trans isomerization of the azobenzene unit under either visible light irradiation or heating enables the α-cyclodextrin ring shuttling back to the azobenzene station. The different ethylene glycol repeating chains in the rotaxanes can affect (1) the isomerization rates of the azobenzene units, i.e. the longer the chain, the faster the isomerization rate, and (2) fluorescent quantum yields of the rotaxanes, i.e. the longer the chain, the lower the fluorescent quantum yield. In addition, the quantum yields of the rotaxanes were enhanced by UV light irradiation and decreased back upon visible light irradiation or heating at 65 °C. The current research provides a fundamental understanding of the working mechanism for photothermal-responsive rotaxanes.
Place, publisher, year, edition, pages
2013. Vol. 3, no 7, 2341-2350 p.
Azide-alkyne cycloaddition, Cis-to-trans isomerization, Cyclodextrin rings, Glycol units, Rotaxanes, Trans-cis isomerization, UV-light irradiation, Visible-light irradiation, Working mechanisms
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-118296DOI: 10.1039/c2ra22171cISI: 000313812400035ScopusID: 2-s2.0-84872695127OAI: oai:DiVA.org:kth-118296DiVA: diva2:605759
QC 201302152013-02-152013-02-142013-02-21Bibliographically approved