Each Atom and Electron Matters: A Continuous Gold Nanocluster Series

Achieving continuous atom-by-atom structural evolution and elucidating the associated quantum size effects in metal nanoclusters remain highly challenging, primarily due to the intrinsic thermodynamic preference for discrete magic-number configurations. In this study, we present a synergistic ligand-engineering strategy that combines dynamic ligand coordination with fluorine chemistry to break this preference. The use of weakly coordinating phosphine ligands facilitates adaptive ligand rearrangement during progressive core expansion, while fluorine-induced noncovalent interactions establish a robust molecular and supramolecular spatial lock, thereby stabilizing cluster molecules and enhancing crystallization. Through this approach, we successfully isolated and structurally characterized an unprecedented continuous series of gold nanoclusters: Au₄₁-Au₄₄. Comprehensive experimental and computational structural and photophysical analyses reveal non-monotonic geometric evolution and atom-specific modulation of electronic structure, thereby providing direct evidence for the principle that "each atom and electron matters" in dictating cluster geometry and electronic structures. Collectively, this work fills the structural gap in medium-sized, phosphine-protected gold nanoclusters and provides a continuous cluster series that serves as an ideal model for probing quantum size effects at the atomic level.