Self-Assembly of Silver Nanoclusters by Cooperative Acetylene Bonding with Mutual Pyridyl Coordination

Abstract

The controlled supramolecular alignment of atomically precise metal nanoclusters is a promising method to unlock unprecedented properties and advanced functions beyond those of the individual monomeric nanoclusters. Conventional protocols for the construction of such assemblies require the use of two or more types of ligands for protecting and interconnecting the nanoclusters, respectively. Herein, a strategy is demonstrated for the hierarchical self-assembly of an alkyne-protected silver nanocluster into a 3D network in the crystalline lattice based on cooperative silver···acetylene coordination and silver···pyridyl coordination by a bifunctional ligand with a simple design. The bent ligand L produces a Cl@Ag₁₄L₁₂ monomer with a helical conformation resembling that of organic tripodal ligands, which assembles into a 3D network as evident from a single-crystal X-ray diffraction analysis. The monomeric and network structures are further characterized using grazing-incidence small-angle X-ray scattering, atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray absorption fine structure, in addition to photoluminescence with a microsecond lifetime in the solid state, exhibiting the success of the strategy toward the design of self-assembled 3D supramolecular arrangements of atomically precise metal nanoclusters using a single, simple ligand.