文献类型：期刊文献

英文题名：A [3]Rotaxane with three stable states that responds to multiple-inputs and displays dual fluorescence addresses

作者：Qu, Da-Hui[1]; Wang, Qiao-Chun[1]; Ma, Xiang[1]; Tian, He[1]

机构：[1]E China Univ Sci & Technol, Lab Adv Mat, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Inst Fine Chem, Shanghai 200237, Peoples R China

年份：2005

卷号：11

期号：20

起止页码：5929

外文期刊名：CHEMISTRY-A EUROPEAN JOURNAL

收录：;EI(收录号：2005439430483);WOS:【SCI-EXPANDED(收录号:WOS:000232567700014)】；

语种：英文

外文关键词：cyclodextrins; fluorescence; molecular shuttle; photoisomerization; rotaxanes

摘要：A [3]-rotaxane molecular shuttle containing two a-cyclodextrin (alpha-CD) macrocycles, an azobenzene unit, a stilbene unit, and two different fluorescent naphthalimide units has been investigated. The azobenzene unit and the stilbene unit can be E/Z-photoisomerized separately by light excited at different wavelengths. Irradiation at 380 nm resulted in the photoisomerization of the azobenzene unit, leading to the formation of one stable state of the [3]rotaxane (Z1-NNAS-2CD); irradiation at 313 nm resulted in the photoisomerization of the stilbene unit, leading to the formation of another stable state of the [3]rotaxane (Z2-NNAS-2CD). ne reversible conversion of the Z1 and Z2 isomers back to the E isomer by irradiation at 450 nm and 280 nm, respectively, is accompanied by recovery of the absorption and fluorescence spectra of the [3]rotaxane. The E isomer and the two Z isomers have been characterized by H-1 NMR spectroscopy and by two-dimensional NMR spectroscopy. The light stimuli can induce shuttling motions of the two alpha-CD macrocycles on the molecular thread; concomitantly, the absorption and fluorescence spectra of the [3]rotaxane change in a regular way. When the alpha-CD macrocycle stays close to the fluorescent moiety, the fluorescence of the moiety become stronger due to the rigidity of the alpha-CD ring. As the photoisomerization processes are fully reversible, the photo-induced shuttling motions of the alpha-CD rings can be repeated, accompanied by dual reversible fluorescence signal outputs. The potential application of such light-induced mechanical motions at the molecular level could provide some insight into the workings of a molecular machine with entirely optical signals, and could provide a cheap, convenient interface for communication between micro- and macroworlds.