Ligand-Induced Structural Evolution and Luminescence Tuning in a Series of Superatomic Ir/Ag Hydride-Containing...

A series of hydride-containing bimetallic 8-electron silver-rich superatomic nanoclusters doped with IrH, formulated as IrHAg₂₀[E₂PR₂]₁₂ (E = S, Se; R = OⁿPr, OⁱPr, Ph), were synthesized via a one-pot strategy in combination with ligand-exchange-induced structure transformation (LEIST), which enabled the generation of capping-atom isomers. Single-crystal X-ray diffraction revealed that modification of the ligand shell drives capping-atom migration, leading to structural diversity with symmetries ranging from C₁ to C₃. Among them, IrHAg₂₀[Se₂P(OⁱPr)₂]₁₂ represents the first Ir/Ag superatomic nanocluster stabilized by Se-donor ligands, thereby expanding the examples of ligand-protected silver-rich superatoms. All four compounds exhibit solid-state PL in the NIR region, with quantum yields reaching up to 10%. Notably, IrHAg₂₀[S₂P(OⁱPr)₂]₁₂ displays the highest PLQY. This enhanced emission is attributed to the asymmetric passivating ligand shell, which induces greater distortion of the superatomic core, thereby increasing the transition dipole moment and leading to a pronounced enhancement of PL intensity. Collectively, these findings highlight the critical role of ligand-induced strain and intramolecular interactions in modulating the luminescence of silver-rich nanoclusters, offering new design principles for emissive superatomic materials.