Boosting the Photoluminescence of Au@Cu ₁₂ Nanoclusters via Strategic Fluorine‐Atom Ligand‐Shell Engineering

Atomically precise metal nanoclusters (NCs) provide a unique platform for exploring structure–property correlations; however, achieving high photoluminescence quantum yields (PLQYs) in solution remains a significant challenge. While core‐doping with heavy atoms, such as gold, is a proven strategy to enhance emission via the “heavy atom effect,” the role of peripheral ligand shell engineering in modulating inter‐cluster interactions and structural dynamics is less explored. Herein, we report a strategic ligand‐engineering approach to improve the photoluminescence of gold‐centered, copper‐rich nanoclusters (Au@Cu 12 ). Incorporating a single fluorine atom at the para position of the aromatic alkynyl ligands, we synthesized two structural isomers: [AuCu 12 {S 2 P(O i Pr) 2 } 6 (CCPhF) 4 ] + ( 1 F ) and [AuCu 12 {S 2 P(O n Pr) 2 } 6 (CCPhF) 4 ] + ( 2 F ). Structural characterization, including high‐precision single‐crystal neutron diffraction, reveals that the strategic fluorine “anchor” introduces a network of hydrogen bonding interactions that effectively restrict surface conformational motion. 2 F achieves an exceptional PLQY of 79% in solution, significantly surpassing its non‐fluorinated predecessor (55%). Our findings demonstrate that subtle surface modifications can lead to significant improvements in optical performance.