Solvent-Controlled Intracluster Reorganization and Intercluster Supramolecular Crystalline Assembly of Au ₁ Ag ₂₄ Nanoclusters

Intercluster assembly is essential for constructing functional crystalline materials. Herein, we demonstrate that the solvent environment can regulate intracluster structural rearrangement and distortion in an atomically precise alloy nanocluster system, thereby driving the formation of a rare 8H-type long-period superlattice arrangement between clusters. Solvent-controlled crystallization of Au 1 Ag 24 (SR) 18 (SR = SPhMe 2 ) in dichloromethane, tetrahydrofuran, and acetone afforded three thermodynamically stable and reversibly interconvertible solvatomorphs. Among them, the unique superstructure with an 8H stacking sequence formed in a dichloromethane environment is particularly notable. Single-crystal X-ray diffraction analysis reveals that, in dichloromethane, distortion of the surface Ag 2 S 3 structural units leads to an asymmetric distribution of the 18 surface thiolate ligands, which, in turn, induces the formation of a rare 8H stacking sequence among the clusters. This 8H superstructure exhibits a long-period stacking feature and is stabilized by a dense and highly directional network of noncovalent intercluster interactions. These results demonstrate that solvent-driven reorganization of the intracluster ligand shell, together with intercluster noncovalent interactions, enables effective regulation of the supramolecular assembly of metal nanoclusters, thereby allowing for precise control over their crystal packing modes.