Thiolated Disc Nanoclusters with Pseudo-6-fold Symmetry

The formation of core-shell metal nanoclusters (NCs) with high symmetry remains significantly challenging. Here, we report the first synthesis and atomically precise structures of two discoidal clusters, Ag₆₉ and Ag₇₈, protected by mixed thiol ligands, both exhibiting rare pseudo-6-fold symmetry, with crystallographic disorder considered. While their sizes and skeletons are similar, the key difference arises from the introduction of Cl^- ions from in situ decomposition of CH₂Cl₂ in the assembly of Ag₆₉. Replacing Cl^-, S^2- ions occupy the same positions in Ag₇₈, leading to stronger silver-sulfur coordination and closer silver-silver distances. Notably, within the crystal lattice of Ag₆₉, an additional Ag78 forms at the same location. Ag₆₉ and Ag₆₈ share an identical outer shell of Ag₅₄S₆(^tBuS)₂₄(^tBuPhS)₂₄, but differ at the core, with Ag₆₉ having Ag₁₅Cl₆(^tBuPhS)₂ and Ag₆₈ having Ag₁₄Cl₆(^tBuS)₂. We also discuss the photoluminescent properties, and the photocatalytic degradation of organic dyes is also discussed. This work provides valuable insights into the formation of high-symmetry metal NCs and their potential applications in photochemistry.