Reversible Phase Change of Organic Compounds Based on Photodimerization Reaction and its Practical Application

以蒽羧酸为原料，通过酯化反应合成了新的蒽类化合物。它们在室温下呈结晶相。在其熔融状态的化合物的UV照射导致的蒽部分的光二聚化。我们发现，一些所得的蒽二聚体在室温下显示固态非晶相，而其他二聚体在光照射过程中显示结晶相。各种实验分析和计算机模拟表明，固态非晶相的形成机制与光二聚体中区域异构体的存在及其在熔融状态下的缓慢扩散有关。蒽光二聚体也表现出热逆反应，从而返回到相应的单体，显示结晶相。利用蒽类化合物的光二聚反应和热逆反应，我们成功地证明了蒽类化合物的光致二聚反应。

New anthracene compounds were synthesized by esterification from anthracenecarboxylic acid and various functional groups. They showed crystalline phase at room temperature. UV irradiation of the compounds in their molten state resulted in photodimerization of the anthracene moiety. We found that some of the resulting anthracene dimers showed solid-state amorphous phase at room temperature, while the other dimers exhibited crystalline phase during photoirradiation. Various experimental analyses and computer simulation suggested that the mechanism of solid-state amorphous phase formation is associated with the existing of regio-isomers in the photodimers and their slow diffusion in the molten state. The anthracene photodimers also showed thermal back reaction and thus returned to the corresponding monomers showing the crystalline phase. Using the photodimerization and thermal back reaction of the anthracene compounds, we successfully demonstrated rewritable photopatterning.