Morimoto Masakazu, Sumi Takaki, Irie Masahiro
Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan.
Materials (Basel). 2017 Sep 2;10(9):1021. doi: 10.3390/ma10091021.
Photoswitching and fluorescent properties of sulfone derivatives of 1,2-bis(2-alkyl-4-methyl-5-phenyl-3-thienyl)perfluorocyclopentene, -, having methyl, ethyl, -propyl, -propyl, and -butyl substituents at the reactive carbons (2- and 2'-positions) of the thiophene 1,1-dioxide rings were studied. Diarylethenes - underwent isomerization reactions between open-ring and closed-ring forms upon alternate irradiation with ultraviolet (UV) and visible light and showed fluorescence in the closed-ring forms. The alkyl substitution at the reactive carbons affects the fluorescent property of the closed-ring isomers. The closed-ring isomers - with ethyl, -propyl, -propyl, and -butyl substituents show higher fluorescence quantum yields than with methyl substituents. In polar solvents, the fluorescence quantum yield of markedly decreases, while - maintain the relatively high fluorescence quantum yields. Although the cycloreversion quantum yields of the derivatives with methyl, ethyl, -propyl, and -propyl substituents are quite low and in the order of 10, introduction of -butyl substituents was found to increase the yield up to the order of 10. These results indicate that appropriate alkyl substitution at the reactive carbons is indispensable for properly controlling the photoswitching and fluorescent properties of the photoswitchable fluorescent diarylethenes, which are potentially applicable to super-resolution fluorescence microscopies.
研究了1,2-双(2-烷基-4-甲基-5-苯基-3-噻吩基)全氟环戊烯砜衍生物的光开关和荧光特性，该衍生物在噻吩1,1-二氧化物环的反应性碳（2-位和2'-位）上具有甲基、乙基、丙基、异丙基和丁基取代基。二芳基乙烯在紫外光(UV)和可见光交替照射下会在开环和闭环形式之间发生异构化反应，并在闭环形式下显示荧光。反应性碳上的烷基取代会影响闭环异构体的荧光特性。具有乙基、丙基、异丙基和丁基取代基的闭环异构体比具有甲基取代基的异构体显示出更高的荧光量子产率。在极性溶剂中，具有甲基取代基的异构体的荧光量子产率显著降低，而具有乙基、丙基、异丙基和丁基取代基的异构体保持相对较高的荧光量子产率。尽管具有甲基、乙基、丙基和异丙基取代基的衍生物的环化反转量子产率相当低，约为10，但发现引入丁基取代基可将产率提高到10的量级。这些结果表明，在反应性碳上进行适当的烷基取代对于正确控制可光开关荧光二芳基乙烯的光开关和荧光特性是必不可少的，这些特性可能适用于超分辨率荧光显微镜。
