Key Laboratory of Material Chemistry for Energy Conversion and Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
State Key Laboratory of Material Processing and Die&Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Langmuir. 2020 Jul 7;36(26):7408-7417. doi: 10.1021/acs.langmuir.0c00964. Epub 2020 Jun 15.
Much attention has been paid to construct photoresponsive host-guest supramolecular gels; however, red-shifting the responsive wavelength remains a formidable challenge. Here, a wholly visible-light-responsive supramolecular gel was fabricated through the host-guest interaction between a β-cyclodextrin (β-CD) dimer and a tetra--methoxy-substituted azobenzene (mAzo) dimer (binary gelator) in DMSO/HO (V/V = 8/2). The minimum gelation concentration of the low-molecular-weight binary gelator was 6 wt % measured via the tube inversion method. The substituted methoxy groups shifted the responsive wavelengths of trans-mAzo and cis-mAzo to the green and blue light regions, respectively. The host-guest interaction between mAzo and β-CD as the driving force for gelation was confirmed using the H-NMR and 2D H NOESY spectra. The supramolecular gel showed good self-supporting ability with a storage modulus higher than 10 Pa. The release of Rhodamine B loaded in the gel as a model drug could be controlled by green light irradiation. We envisioned the potential applications of the wholly visible-light-responsive supramolecular compounds ranging from biomedical materials to smart materials.
人们高度关注构建对光响应的主体-客体超分子凝胶；然而，红移响应波长仍然是一个艰巨的挑战。在这里，通过β-环糊精（β-CD）二聚体和四--甲氧基取代偶氮苯（mAzo）二聚体（二元凝胶因子）在 DMSO/H2O（V/V = 8/2）中的主客体相互作用，制备了完全对可见光响应的超分子凝胶。通过管倒置法测量，低分子量二元凝胶因子的最低凝胶浓度为 6wt%。取代的甲氧基基团分别将反式-mAzo 和顺式-mAzo 的响应波长红移至绿光和蓝光区域。使用 1H-NMR 和二维 1H NOESY 谱图证实了 mAzo 和β-CD 之间的主体-客体相互作用是凝胶形成的驱动力。超分子凝胶具有良好的自支撑能力，储能模量高于 10Pa。作为模型药物负载的罗丹明 B 的释放可以通过绿光照射来控制。我们设想了完全对可见光响应的超分子化合物在从生物医学材料到智能材料的潜在应用。
