Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo, 171-8501, Japan.
Photochem Photobiol Sci. 2020 Jun;19(6):783-789. doi: 10.1039/d0pp00064g. Epub 2020 Oct 27.
Diarylethene derivatives having benzothiophene S,S-dioxide groups undergo turn-on mode fluorescence photoswitching. For the practical application to super-resolution fluorescence microscopy, photoswitchable fluorescent molecules are desired to be resistant against photodegradation. Here we synthesized turn-on mode fluorescent diarylethenes having electron-withdrawing (trifluoromethyl or nitro) or electron-donating (methyl, methoxy, or dimethylamino) substituents on phenyl rings at 6- and 6'-positions of the benzothiophene S,S-dioxide groups and examined the effect of the substituents on the photoswitchiing performance. The derivatives having electron-donating substituents showed significant bathochromic shifts of the absorption and fluorescence spectra. The cycloreversion quantum yield was increased by introducing electron-withdrawing substituents, while it was decreased by the electron-donating ones. Introduction of electron-donating substituents was found to remarkably improve the fatigue resistance of the fluorescent diarylethene under continuous ultraviolet (UV) irradiation. Such highly fatigue-resistant fluorescent diarylethenes are useful for super-resolution fluorescence imaging or single-molecule fluorescence tracking.
具有苯并噻吩 S，S-二氧化物基团的二芳基乙烯衍生物经历开模式荧光光致开关。为了将其实际应用于超分辨率荧光显微镜，希望光致开关荧光分子能够抵抗光降解。在这里，我们合成了在苯并噻吩 S，S-二氧化物基团的 6-和 6'-位的苯基环上具有吸电子（三氟甲基或硝基）或供电子（甲基，甲氧基或二甲氨基）取代基的开模式荧光二芳基乙烯，并研究了取代基对光致开关性能的影响。具有供电子取代基的衍生物显示出吸收和荧光光谱的显著红移。通过引入吸电子取代基，可以增加环化量子产率，而通过供电子取代基则会降低环化量子产率。引入供电子取代基可以显著提高荧光二芳基乙烯在连续紫外（UV）照射下的抗疲劳性。这种高抗疲劳荧光二芳基乙烯可用于超分辨率荧光成像或单分子荧光跟踪。
