Helical Self-Assembly-Induced Singlet–Triplet Emissive Switching in a Mechanically Sensitive System

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• 作者：Hongwei Wu ; Yunyun Zhou ; Liyuan Yin ; Cheng Hang ; Xin Li ; Hans Ågren ; Tao Yi ; Qing Zhang ; Liangliang Zhu
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：139
• 期：2
• 页码：785-791
• 全文大小：528K
• ISSN：1520-5126

文摘

In nanoscience, chirality has shown a significant ability to tune materials’ electronic properties, whereas imposing macrochirality into the regulation of singlet–triplet features of organic optoelectronics remains a challenging research topic. Since the tuning for singlet and triplet excited-state properties in a single π-functional molecule connects to its multicolor luminescent application and potential improvement of internal quantum efficiency, we here report that supramolecular chirality can be employed to toggle the singlet and triplet emissions in a well-designed asterisk-shaped molecule. Employing a hexathiobenzene-based single luminophore as a prototype and functionalizing it with chiral α-lipoiate side groups, we find that helical nanoarchitectures can accordingly form in mixed DMF/H₂O solution. On this basis, switching between fluorescence and phosphorescence of the material can be realized upon helical self-assembly and dissociation. Such a behavior can be attributed to a helical-conformation-dependent manipulation of the intersystem crossing. Furthermore, reversible mechanoluminescence of the corresponding solid sample was also observed to rely on an analogous molecular self-assembly alternation. These results can probably provide new visions for the development of next-generation supramolecular chiral functional materials.