1,2-Bis(benzo[b]thiophen-3-yl)ethene derivatives, which possess thermally irreversible and fatigue resistant photochromic properties, were synthesized, cis-1,2-Dicyano-1,2-bis(2-methylbenzo[b]thiophen-3-yl)ethene 1a and 2,3-bis(2-methylbenzo[b]thiophen-3-yl)maleic anhydride 2a underwent reversible photocyclization to produce red-colored closed-ring forms with λmax at 507 nm and 544 nm, respectively. The closed-ring forms were stable for more than 3 weeks at 80 °C. The coloration/decoloration (ring closure/opening)cycles were able to be repeated more than 104 times with keeping the adequate photochromic performance.

中文翻译：

---

热不可逆光致变色系统。1,2-双(苯并[b]噻吩-3-基)乙烯衍生物的可逆光环化

合成了具有热不可逆性和抗疲劳光致变色性能的 1,2-双（苯并[b]噻吩-3-基）乙烯衍生物，cis-1,2-Dicyano-1,2-bis(2-methylbenzo[ b]噻吩-3-基）乙烯 1a 和 2,3-双（2-甲基苯并[b]噻吩-3-基）马来酸酐 2a 经历可逆光环化，产生红色闭环形式，λmax 在 507 nm 和分别为 544 nm。闭环形式在 80 °C 下可稳定超过 3 周。在保持足够的光致变色性能的情况下，着色/脱色（闭环/开环）循环能够重复超过 104 次。