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Atom-precise metal nanoclusters (NCs) with large bulk (nuclearity >60) are important species for insight into the embryonic phase of metal nanoparticles and their top-down etching synthesis. Herein, we report a metastable rod-shaped 70-nuclei copper-hydride NC, [Cl@Cu 70 H 22 (PhC≡C) 29 (CF 3 COO) 16 ] 2+ ( Cu 70 ), with Cl - as the template, in which the Cl@Cu 59 kernel adopts a distinctive metal packing mode along the bipolar direction, and the protective ligand shell exhibits corresponding site differentiation. In terms of metal nuclearity, Cu 70 is the largest alkynyl-stabilized Cu-hydride cluster to date. As a typical highly active intermediate, Cu 70 could undergo a transformation into a series of robust modularly assembled Cu clusters ( B -type Cu 8 , A-A -type Cu 22 , A-B -type Cu 23 , and A-B-A -type Cu 38 ) upon etching by p - tert -butylthiacalix[4]arene (H 4 TC 4 A), which could not be achieved by "one-pot" synthetic methods. Notably, the patterns of A and B blocks in the Cu NCs could be effectively modulated by employing appropriate counterions and blockers, and the modular assembly mechanism was illustrated through comprehensive solution chemistry analysis using HR-ESI-MS. Furthermore, catalytic investigations reveal that Cu 38 could serve as a highly efficient catalyst for the cycloaddition of propargylic amines with CO 2 under mild conditions. This work not only enriched the family of high-nuclear copper-hydride NCs but also provided new insights into the growth mechanism of metal NCs.

Understanding how the chiral or achiral section in chiral nanostructures contributes to circularly polarized light emission (CPLE) at the atomic level is of fundamental importance. Here, we report two pairs of atomically precise enantiomers of homosilver ( R / S -Ag 12 Ag 32 ) and heterometal ( R / S- Au 12 Ag 32 ) clusters. The geometrical chirality of R / S -Ag 12 Ag 32 arises from the chiral ligand and interface consisting of positive moieties of Ag 32 ( R / S -PS) 24 . The circular dichroism of R / S -Ag 12 Ag 32 is active, but CPLE-silent. A complete metal change from Ag 12 to Au 12 in the achiral core section of S 2- @M 12 @S 8 engenders isomorphous heterometal R / S -Au 12 Ag 32 , which activates CPLE. We further quantify the contributions of achiral and chiral sections and for the first time unveil that heterometal bonding (Au 12 -Ag 32 ) at the linkage varies the delocalization of orbitals and proportion of achiral and chiral section in electron transition-involved orbitals, thus activating CPLE. Based on these unique atomically precise homochiral metal clusters, our work provides a new insight into the contributions of achiral and chiral sections to the origin of chiroptical response of chiral metal clusters, paving the way to advance the development of CPLE nanoparticles.