On-Stage and Behind-the-Scenes: Solvent-Directed Structural Transformation and Optical Properties of Metal Clusters.

Understanding the intrinsic relationship between structure conversion and property response is one of the central challenges in the design of functional materials. In recent years, atomically precise metal clusters, featuring highly tunable geometrical configurations and discrete electronic energy levels, have emerged as ideal model systems for elucidating structure-property correlations. Among various external stimuli that trigger structural transformations of metal clusters, solvents play a unique and active role: beyond serving as reaction or dissolution media, they can systematically induce diverse structural conversions of metal clusters and thereby profoundly modulate their optical properties. In view of the current lack of a unified theoretical framework connecting solvent-directed structural conversion with optical responses of metal clusters, this review first systematically summarizes the typical types of solvent-induced structural transformations in metal clusters. It then provides an in-depth analysis of the microscopic mechanisms underlying solvent-driven structural evolution and their intrinsic influence on optical properties. Finally, the fundamental issues, remaining challenges, and future perspectives in this emerging field are discussed. This review aims to provide a theoretical foundation and methodological guidance for solvent-controlled structural transformations and optical performance optimization of metal clusters.