Solvent‐Induced Reverse‐Ostwald Ripening: Structure Conversion from Ag ₅₆ to Ag ₄₅ Clusters and Its Impact on Catalytic Reduction of 4‐Nitrophenol

ABSTRACT Controlled structure transformation in metal clusters is crucial for accessing novel architectures and understanding their structure‐property correlations. Herein, we report a solvent‐induced reverse‐Ostwald ripening process between two atomically precise silver clusters, Ag ₅₆ and Ag ₄₅ , which exhibit solvent‐dependent structure variation: Ag ₅₆ remains stable in dichloromethane, whereas exposure to pentane induces conversion to Ag ₄₅ . The compositions and structures of both clusters were determined by electrospray ionization mass spectrometry (ESI‐MS) and single‐crystal X‐ray diffraction (SXRD). Structure analysis indicates that the Ag ₄₅ forms via fragmentation and reorganization of the Ag ₅₆ framework, distinct from the conventional Ostwald ripening observed in larger nano‐systems. Although Ag ₄₅ and Ag ₅₆ share certain structural similarities, Ag ₄₅ exhibits superior stability and higher catalytic activity for the reduction of 4‐nitrophenol (4‐NP) than Ag ₅₆ . Density functional theory (DFT) calculations further elucidate the catalytic reduction pathway on Ag ₄₅ . This work demonstrates a solvent‐mediated reverse‐Ostwald ripening pathway in silver clusters, providing atomic‐level insights into active site construction and offering a blueprint for designing robust, cluster‐based catalysts.