Dehiwala Liyanage Chamathka, Ortiz-Garcia José J, Struckmeier Annalena, McCoy Christian L, Kienzler Michael A, Quardokus Rebecca C
Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States.
J Phys Chem Lett. 2024 Apr 18;15(15):4082-4087. doi: 10.1021/acs.jpclett.4c00096. Epub 2024 Apr 8.
Azobenzenes are fascinating molecular machines that can reversibly transform between two isomeric forms by an external stimulus. Diazocine, a type of bridged azobenzene, has been shown to possess enhanced photoexcitation properties. Due to the distortion caused by the ethyl bridge in the E-isomer, the Z-form becomes the thermodynamically stable configuration. Despite a comprehensive understanding of its photophysical properties, there is still much to learn about the behavior of diazocine on a metal surface. Here we show the operando photoswitching of diazocine molecules deposited directly on a Au(111) surface using scanning tunneling microscopy. Molecules were shown to aggregate into disordered islands with edge sites being susceptible to photon-induced movement. A few molecules were shown to undergo directional movement under UV irradiation with the motion reversed under blue light exposure. These findings contribute new insight into the activity of single and ensemble molecular systems toward purposefully guided motion.
偶氮苯是一种引人入胜的分子机器，能够通过外部刺激在两种异构体形式之间可逆地转变。重氮辛，一种桥连偶氮苯，已被证明具有增强的光激发特性。由于E-异构体中乙基桥引起的扭曲，Z-形式成为热力学稳定构型。尽管对其光物理性质有了全面的了解，但关于重氮辛在金属表面的行为仍有许多需要研究的地方。在这里，我们使用扫描隧道显微镜展示了直接沉积在Au(111)表面的重氮辛分子的原位光开关特性。分子被证明聚集形成无序岛，边缘位点容易受到光子诱导的移动影响。少数分子在紫外线照射下会发生定向移动，在蓝光照射下运动方向会反转。这些发现为单分子和分子集合系统朝着有目的引导运动的活性提供了新的见解。
