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31.
A dyad bearing diarylethene and spiropyran units were synthesized. Ultraviolet light, visible light, H+, and Fe3+ inputs induce the multiple interconversion among the colorless diarylethene with spiropyran form (3), the colored closed form of diarylethene with spiropyran form (4), ME (5), MEH (6, 7) and MEH·Fe3+ (8). The efficient energy transfer from the anthracene emission to MEH·Fe3+ or ME·Fe3+ form was achieved. Using multi-mode photo switching in a dyad 3, logic gates may be built. 相似文献
32.
We previously found that a simple spiropyran derivative (1:1′,3′,3′-trimethyl-6-nitro-spiro-[2H-1-benzopyran-2,2′-indoline]) behaves as a selective and sensitive cyanide anion (CN−) receptor in aqueous media under UV irradiation13. The receptor, when irradiated by UV light in a water/MeCN mixture, creates a CN−-selective absorption band via a nucleophilic addition of CN− to 1 (formation of the 1-CN− species) and allows quantitative determination of very low levels of CN−. In the present work, effects of pH and water content on the response of 1 to anions were studied to clarify the detailed properties of 1. In aqueous media, 1 reacts selectively with CN−regardless of pH and water content, but the reaction is suppressed by a decrease in pH and an increase in water content due to the protonation of CN−. In contrast, in pure MeCN, addition of F− also creates a new absorption band, as does CN−. This is promoted via a nucleophilic interaction between 1 and F− in a 1:2 stoichiometry (formation of the 1-2F− species). The 1-CN− and 1-2F− species have different photochemical properties; the 1-CN− species is stable upon UV irradiation, while the UV irradiation of the 1-2F− species leads to a decomposition of the spiropyran platform. 相似文献
33.
Zheng Kai Si Qing Zhang Min Zhao Xue Yuan Yuan Zhu Liang Ming Qiao Rong Sheng Yan Gang Liu 《中国化学快报》2011,22(9):1025-1028
Three novel bis-chalcone derivatives with different alkyldioxy spacers were synthesized and dispersed into polymethyl methacrylate(PMMA) chloroform solution with 6-nitro-1’-ethyl-3’,3’-dimethylspiro-2H-1-benzopyran-2,2’-indoline(ESP) to prepare photochromic PMMA films in a facile way.After irradiation with 365 nm UV light,the photocrosslinking reaction between chalcone units was proved to retard the dccolorization of merocyanine form of the photochromic spiropyran effectively,as results of the steric hindrance produced by photocycloaddition of chalcone groups.It has been found that the bis-chalcone molecule with the shortest spacer has the most effective stabilizing effect on retardation of decoloration of spiropyran. 相似文献