Azoarenes remain privileged photoswitches – molecules that can be interconverted between two states using light – enabling a huge range of light addressable multifunctional systems and materials. Two key innovations to improve the addressability and Z-isomer stability of the azoarenes have been ortho-substitution of the benzene ring(s) or replacement of one of the benzenes for a pyrazole (to give arylazopyrazole switches). Here we study the combination of such high-performance features within a single switch architecture. Through computational analysis and experimental measurements of representative examples, we demonstrate that ortho-benzene substitution of the arylazopyrazoles drastically increases the Z-isomer stability and allows further tuning of their addressability. This includes the discovery of new azopyrazoles with a Z-isomer thermal half-life of ≈46 years. Such results therefore define improved designs for high performance azo switches, which will allow for high precision optically addressable applications using such components.
偶氮芳烃仍然是优越的光切换分子,可以在两种状态之间使用光进行相互转换,从而实现广泛的光可寻址多功能系统和材料。为了提高偶氮芳烃的可寻址性和Z-异构体稳定性,进行了两项关键创新:对苯环的邻位取代或将其中一个苯环替换为吡唑(形成芳基偶氮吡唑开关)。在这里,我们研究了在单个开关结构中结合这些高性能特征。通过代表性示例的计算分析和实验测量,我们证明了对芳基偶氮吡唑的邻位苯环取代显著增加了Z-异构体的稳定性,并允许进一步调节它们的可寻址性。这包括发现具有约46年Z-异构体热半衰期的新偶氮吡唑。因此,这些结果定义了用于高性能偶氮开关的改进设计,将允许使用这些组件进行高精度光可寻址应用。