Low-molecular-weight supramolecular hydrogels are of significant attractive soft materials as particular functions can be facilely introduced by the straightforward fabrication of such self-assembled systems. In this ...Low-molecular-weight supramolecular hydrogels are of significant attractive soft materials as particular functions can be facilely introduced by the straightforward fabrication of such self-assembled systems. In this study, an azobenzene-bridged dicationic pyridinium salt was synthesized, from which photoresponsive supramolecular hydrogel could be fabricated through the π-π stacking and hydrophobic interactions in the aqueous solution. By taking advantages of the UV-vis light induced E/Z photoisomerization behaviors of the incorporated azobenzene photochromophore, reversible gel-sol transformation of such supramolecular hydrogel could be achieved under the alternating UV-vis irradiation conditions. We believed that this photoresponsive supramolecular hydrogel will be a good supplementary in the creation of intelligent soft material.展开更多
Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and ...Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and dichloromethane is described. The reaction has intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes and a possible mechanism is also suggested.展开更多
Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methyle...Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methylenes than compound 5. UV\|Vis spectra of compounds 5 and 6 were the simple superposition of the absorbance of the azobenzene and pyrazoling and showed that pyrazoline had no effect on the isomerization of azobenzene. When there were two methylenes between azobenzene and pyrazoline, the fluorescent intensity of compound 5 decreased greatly compared with that of compound 6. It means that the intramolecular Electronic Energy Transfer has taken place in compound 5. In compound 6, this process could not occur because of the longer flexible chain between the two chromophores.展开更多
基金the National Natural Science Foundation of China (Nos. 21502216 and 21602205)Natural Science Foundation of Zhejiang Province (No. LQ19B020019) for the financial support to this research
文摘Low-molecular-weight supramolecular hydrogels are of significant attractive soft materials as particular functions can be facilely introduced by the straightforward fabrication of such self-assembled systems. In this study, an azobenzene-bridged dicationic pyridinium salt was synthesized, from which photoresponsive supramolecular hydrogel could be fabricated through the π-π stacking and hydrophobic interactions in the aqueous solution. By taking advantages of the UV-vis light induced E/Z photoisomerization behaviors of the incorporated azobenzene photochromophore, reversible gel-sol transformation of such supramolecular hydrogel could be achieved under the alternating UV-vis irradiation conditions. We believed that this photoresponsive supramolecular hydrogel will be a good supplementary in the creation of intelligent soft material.
文摘Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and dichloromethane is described. The reaction has intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes and a possible mechanism is also suggested.
文摘Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methylenes than compound 5. UV\|Vis spectra of compounds 5 and 6 were the simple superposition of the absorbance of the azobenzene and pyrazoling and showed that pyrazoline had no effect on the isomerization of azobenzene. When there were two methylenes between azobenzene and pyrazoline, the fluorescent intensity of compound 5 decreased greatly compared with that of compound 6. It means that the intramolecular Electronic Energy Transfer has taken place in compound 5. In compound 6, this process could not occur because of the longer flexible chain between the two chromophores.
