Metallomacrocyclic Ligands Stabilized Icosahedral Superatomic Nanoclusters With NIR-I to NIR-II Phosphorescence Modulation

Coinage metal nanoclusters with near-infrared-II (NIR-II, λ_PL > 1000 nm) photoluminescence hold great promise for biological applications. Here, we report the first icosahedral M₁₃ cluster exhibiting NIR-II phosphorescence, achieved through an unprecedented metallomacrocyclic ligand coordination combined with an alloying strategy, denoted as M₁₃@M₆ clusters. The metallomacrocyclic ligands strongly regulate the photophysical properties of the M₁₃ core, governing its lowest triplet excited state (T₁) and enabling a markedly red-shifted emission. They also provide a distinctive “core surface→metallomacrocycle→inner core” pathway for stepwise silver doping. Combined theoretical calculations and emission spectra reveal that doping-induced charge transfer between the M₁₃ core and M₆ metallomacrocycles drives the photoluminescence shift from the NIR-I to the NIR-II region. Furthermore, functionalization of the metallomacrocyclic ligands with bulky pyrene groups enhances NIR-II emission by an order of magnitude. Catalytic studies demonstrate that site-specific tuning of metal composition within M₁₃@M₆ clusters enables nanometer-scale modulation of catalytic activity, highlighting the versatility of metallomacrocyclic ligands for regulating both luminescence and catalytic properties. This work not only extends coinage metal cluster protection from conventional organic ligands to metallomacrocycles but also provides a systematic framework for NIR-II emission modulation through inner-core and metallomacrocycle doping, ligand engineering at the coordination interface, and outer-sphere functionalization.