Single-molecule fluorescence photoswitching based on the photochromic conformational changes

合成了一些在二芳基乙烯的活性碳上引入荧光单元的二芳基乙烯衍生物，并研究了它们的荧光光开关性能。在这些研究中，意外地发现了一个意想不到的光反应，其中光开关单元的光环化反应与非吸收波长的光进行。多个实验结果表明，该非预期反应来源于二芳基乙烯单元的三重态。这一结果被推广到合成具有非破坏性读出能力的新型单分子荧光光开关分子。这种分子的荧光和光致变色性能使我们能够实现在溶液中甚至在单分子水平上的非破坏性读出的荧光光开关。

Some diarylethene derivatives, which introduce a fluorescent unit at the reactive carbon of diarylethenes were synthesized and studied its fluorescence photoswitching properties. In these studies, an unexpected photoreaction, in which the photocyclization reaction of the photoswitching unit proceeds with non-absorbing wavelength light, was accidently found. From several experiments, it is suggested that the unexpected reaction proceeds from the triplet-state of diarylethene unit. This result was extended to the synthesis of a novel single-molecular fluorescent photoswitching molecule with the non-destructive readout capability. The fluorescence and photochromic performances of this molecule allow us to achieve the fluorescence photoswitching with non-destructive readout in the solution as well as even at the single-molecule level.