Stitching Atom‐Precise Ag 6 NCs in Cyclodextrin Metal‐Organic Framework: Chirality Induction and Second Harmonic Generation

ABSTRACT Cyclodextrin‐based metal–organic frameworks (CD‐MOFs) has attracted considerable attention owing to their high crystallinity, water solubility, and biocompatibility. However, integrating atomically precise metal nanoclusters (MNCs) into CD‐MOFs remains largely unexplored. Only a few reports describe encapsulating MNCs within CD‐MOFs, but none have crystallographically elucidated the structural aspects of MNCs‐embedded CD‐MOFs. Moreover, the site‐specific positioning of MNCs in MOF—highly desirable for developing active catalysts and modulating properties—remains an unsolved challenge. Herein, we report the atomically precise hybrid assembly of Ag 6 nanoclusters (NCs) within γ‐cyclodextrin (γ‐CD) MOFs. Ultrasmall Ag 6 NCs are immobilized within the porous alkali metal ion–coordinated (K + , Rb + , Cs + ) γ‐CD framework, affording a well‐defined metal nanocluster‐γ‐CD‐MOF architecture at the nanoscale. Single‐crystal X‐ray diffraction unambiguously resolves a series of Ag 6 NC–incorporated γ‐CD MOFs, denoted as Ag 6 /M + /γ‐CD (M = K, Rb, Cs). Incorporation of the Ag 6 NCs profoundly modulates their intrinsic photophysical properties, induces supramolecular chirality, and enables second‐harmonic generation (SHG). Furthermore, the Ag 6 /M + /γ‐CD systems exhibit thermally activated delayed fluorescence, as corroborated by detailed theoretical calculations. Notably, these hybrid frameworks display pronounced circularly polarized luminescence, arising from chirality transfer from the γ‐CD host and the spatially organized ligand shell surrounding the luminescent Ag 6 NC assemblies.