Crystalline systems consisting of small-molecule building blocks have emerged as promising materials with diverse applications. It is of great importance to characterize not only their static structures but also the conversion of their structures in response to external stimuli. Femtosecond time-resolved crystallography has the potential to probe the real-time dynamics of structural transitions, but, thus far, this has not been realized for chemical reactions in non-biological crystals. In this study, we applied time-resolved serial femtosecond crystallography (TR-SFX), a powerful technique for visualizing protein structural dynamics, to a metal–organic framework, consisting of Fe porphyrins and hexazirconium nodes, and elucidated its structural dynamics. The time-resolved electron density maps derived from the TR-SFX data unveil trifurcating structural pathways: coherent oscillatory movements of Zr and Fe atoms, a transient structure with the Fe porphyrins and Zr₆ nodes undergoing doming and disordering movements, respectively, and a vibrationally hot structure with isotropic structural disorder. These findings demonstrate the feasibility of using TR-SFX to study chemical systems.

由小分子结构单元组成的晶体系统已成为具有多种应用的有前途的材料。不仅表征它们的静态结构，而且表征它们响应外部刺激的结构转换也非常重要。飞秒时间分辨晶体学具有探测结构转变的实时动态的潜力，但迄今为止，这对于非生物晶体中的化学反应尚未实现。在这项研究中，我们将时间分辨串行飞秒晶体学（TR-SFX）（一种可视化蛋白质结构动力学的强大技术）应用于由铁卟啉和六锆节点组成的金属有机框架，并阐明了其结构动力学。从 TR-SFX 数据导出的时间分辨电子密度图揭示了三叉结构路径：Zr 和 Fe 原子的相干振荡运动、Fe 卟啉和 Zr ₆节点分别经历隆起和无序运动的瞬态结构，以及振动具有各向同性结构无序的热结构。这些发现证明了使用 TR-SFX 研究化学系统的可行性。