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-, S2- 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.