Abstract：
Nucleosidic diarylethenes (DAEs) have evolved from an emerging class of photochromes into a well-established option for integrating photochromic functionalities into biological systems. However, a comprehensive understanding of how chemical structure influences their photochromic properties remains essential. While structural features, such as an inverse connection between the aryl residues and the ethene bridge, are well-documented for classical DAEs, their application to nucleosidic DAEs has been underexplored. In this study, we address this gap by developing three distinct types of inverse nucleosidic DAEs - semi-inverse thiophenes, semi-inverse uridines and inverse uridines. We successfully synthesized these compounds and conducted comprehensive analyses of their photostationary states, thermal stability, reversibility, and reaction quantum yields. Additionally, we conducted an in-depth comparison of their photochromic properties with those of their normal-type counterparts. Among the synthesized compounds, seven semi-inverse thiophenes exhibited the most promising characteristics. Notably, these compounds demonstrated excellent fatigue resistance, with up to 96% retention of photochromic activity over 40 switching cycles, surpassing the performance of all comparable nucleosidic DAEs reported to date. These findings hold significant promise for future applications in various fields.
摘要：
核二芳基乙烯（DAE）已经从一类新兴的光致变色化合物发展成为将光致变色功能整合到生物系统中的公认选择。然而,全面了解化学结构如何影响其光致变色性能仍然至关重要。虽然结构特征，例如芳基残基和乙烯桥之间的反向连接，对于经典的DAE有很好的记录，它们在核苷DAE中的应用还没有得到充分的开发。在这项研究中,我们通过开发三种不同类型的反核苷DAE-半反噻吩来解决这个差距，半反尿酸和反尿酸。我们成功地合成了这些化合物，并对它们的光稳态进行了全面的分析，热稳定性，可逆性,和反应量子产率。此外,我们对它们的光致变色性能与正常类型的光致变色性能进行了深入的比较。在合成的化合物中，七个半反相噻吩表现出最有希望的特征。值得注意的是,这些化合物表现出优异的抗疲劳性，在40个开关周期内，光致变色活性保留高达96%，超过迄今为止报告的所有可比核苷DAE的性能。这些发现为未来在各个领域的应用带来了巨大的希望。
