Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4765710 | Dyes and Pigments | 2018 | 7 Pages |
â¢Photoswitchable [n]rotaxanes based on dithienylethene unit were synthesized.â¢The photochromic properties and fluorescence behaviors were also investigated.â¢Non-covalent components could influence the photoswitching properties.â¢Photochromic signal (such as molar absorption coefficient) t can be integrated.
Mechanically interlocked structures such as rotaxanes and catenanes provide a novel backbone for constructing functional materials with unique structural characteristics. In this study, the novel photoswitchable [n]rotaxanes 11 and 12 based on dithienylethene unit were efficiently synthesized by the classical template-directed clipping approach. And their structures were well-confirmed by NMR, MS and elemental analysis. Investigation on photochromic properties indicated that dithienylethene-based [n]rotaxanes had good reversibility and excellent fatigue resistance upon irradiation with UV or visible light. And they displayed also excellent fluorescence switchable behavior. Interestingly, It was found that [2]rotaxane 11 had better photoisomerization properties in comparison to its corresponding macrocycle 4, which indicated that the non-covalent components on the [2]rotaxane 11 could influence the photoswitching properties. Furthermore, the mechanically interlocked molecules containing two dithienylethene backbones displayed around a 2-fold increase in the molar absorption coefficient compared with that of the mono dithienylethene derivative, which was consistent with the reported [n]rotaxane 9 and 10.
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