新型1,8-萘酰亚胺类光控双色荧光分子开关的合成及性质

Synthesis and Properties of Novel Dual-Color Fluorescent Molecular Switch with 1,8-Naphthalimide Unit

设计合成了三种新型键合螺吡喃单元的1,8-萘酰亚胺类化合物.光致变色性质研究结果表明:三种化合物与经典螺吡喃相比,其开环过程光响应时间较长或难以检测到其开环的部花菁结构,分析了其光响应时间变长的原因.SP3分子中由于存在强吸电子基,其在固体介质以及有机溶剂中光致变色现象较为明显,在不同的有机溶剂中显示出了负的溶剂效应,螺吡喃单元开环体的吸收波长没有明显的改变.荧光性能检测发现:化合物SP1、SP2在硅胶中光照前后有较为明显的荧光颜色改变,在聚甲基丙烯酸甲酯(PMMA)中和有机溶剂中检测不到其光照前后荧光的变化.未检测到化合物SP3光照前后在丙酮中的荧光改变,但是在聚乙二醇(200)中光照前发射绿色荧光,光照后变为橙黄色荧光,荧光光谱也检测到了其变化过程.SP3在薄层硅胶中光照前后发生的荧光颜色改变更为明显,随着照射时间的延长其荧光由绿色变为黄绿色,橙黄色最后变为红色,化合物在PMMA膜中的荧光光谱也表明了化合物SP3具有光控双色荧光分子开关性能.

Spiropyran compound is widely used as an important class of photochromic compounds. Three new types of 1,8-naphthalimide compounds with spiropyran unit were synthesized and the structures were characterized. The photochromic characteristics research shows that their response time of the ring opening process is long even difficult to be detected comparing the classical spiropyran. And the reason of their prolonged ring opening reaction is analyzed theoretically and structurally. The photochromic properties of SP3 are more obvious both in solid medium and organic solvents due to the presence of the strong electro-withdraw substituent. It turned into orange red from yellow in polyethylene glycol（200） and from yellow to grey purple in acetone. The investigation of the UV-Vis absorption spectra also showed its negative solvent effect in different organic solvents. There is no significant difference in the absorption wavelength of the spiropyran unit ring opened after irradiation compared with the standard one. The fluorescence properties of the three compounds were investigated to find that SP1 and SP2 showed obvious fluorescence color changes prior and after the UV irradiation in the silica gel, and no fluorescence color changes were detected in polymethylmethacrylate（PMMA） and organic solvents. Fluorescence changes of compound SP3 in acetone were not detected after the UV irradiation. The compound SP3 emitted green fluorescence and became orange yellow fluorescence after ultrasonic irradiation in polyethylene glycol（200）. The changing process was detected by fluorescence spectrum. The fluorescence color change of SP3 is more obvious in the thin layer silica gel before and after irradiation. As time elapses, the green fluorescence converted to red one and turned into red from orange yellow eventually. The fluorescence spectrum of the compounds in PMMA film showed that the compound SP3 played the role of a dual-color fluorescent molecular switch. Because of the amino-group in its molecular structure, this dual-color fluorescent molecular switch is suitable for application in labeling biological system.