Designed construction of two new atom-precise three-dimensional and two-dimensional Ag12 cluster-assembled materials

Abstract

Silver cluster-assembled materials (SCAMs) are well-defined crystalline extended materials hallmarked by their unique geometric structures, atomically precise designability and functional modularity. In this study, we report for the first time the synthesis of a (3,6)-connected three-dimensional (3D) SCAM, [Ag₁₂(S^tBu)₆(CF₃COO)₆(TPMA)₆]_n (designated as TUS 6), TPMA = tris(pyridine-4-ylmethyl)amine, by assembling Ag₁₂ cluster nodes with the help of a tritopic linker TPMA. Besides, we also prepared a two-dimensional (2D) SCAM, [Ag₁₂(S^tBu)₆(CF₃COO)₆(TPEB)₆]_n (described as TUS 7), TPEB = 1,3,5-tris(pyridine-4-ylethynyl)benzene, by reticulating Ag₁₂ nodes with a tritopic linker TPEB. Characterized by microscopic and diffraction analyses, the SCAMs revealed distinct morphologies, structural robustness, and phase purity. This paper elucidates how the binding with the organic linkers alters the symmetry of the silver nanoclusters (NCs). Changes in the symmetry of discrete NCs to assembled structures have not been reported yet. This study provides an atomic-level explanation of the transformation of symmetry from NCs to extended structures.