Auxiliary ligand-induced assembly of atomically precise silver clusters

Establishing the correlation between inter-cluster assembly and auxiliary ligands at the atomic level is crucial for the development of metal cluster science. In this work, we report the successful preparation and characterization of three Ag clusters, discrete 0-D Ag₅₁S₆Cl₃(ⁱPrS)₂₁(TsO)₁₅CH₃CN (0-D Ag₅₁, ⁱPrS⁻ = isopropanethiolate, TsO⁻ = toluenesulfonate), 1-D {Ag₃₈S₄ (ⁱPrS)₁₈(PhCOO)₁₂}_n (1-D Ag₃₈, PHCOO⁻ = benzoate), and 2-D {Ag₂₀(SO₄)Cl₂(ⁱPrS)₁₀(NO₃)₆}_n (2-D Ag₂₀), using a delicate auxiliary-ligand-induced strategy. Structural analyses reveal that the types of auxiliary ligands can readily affect the structure and dimensionality of resulting Ag clusters. The addition of different surface auxiliary ligands from TsO⁻ to PhCOO⁻ and then to NO₃⁻ leads to the formation of 0-D Ag₅₁ to 1-D Ag₃₈ and then to 2-D Ag₂₀ clusters under otherwise identical reaction conditions, respectively. The resulting Ag clusters exhibited structure-related optical/luminescence properties and distinct bathochromic shifts as revealed by the temperature-dependent luminescence and single-crystal X-ray diffraction studies.