Ag₂₂ Nanoclusters with Thermally Activated Delayed Fluorescence Protected by Ag/Cyanurate/Phosphine Metallamacrocyclic Monolayers through In‐Situ Ligand Transesterification

The composition of protection monolayer exerts great influence on the molecular and electronic structures of atomically precise monolayer protected metal nanoclusters. Four isostructural Ag/cyanurate/phosphine metallamacrocyclic monolayer protected Ag 22 nanoclusters are synthesized by kinetically controlled in‐situ ligand formation‐driven strategy. These eight‐electron superatomic silver nanoclusters feature an unprecedented interfacial bonding structure with diverse E‐Ag (E=O/N/P/Ag) interactions between the Ag 13 core and metallamacrocyclic monolayer, and displays thermally activated delayed fluorescence (TADF), benefiting from their distinct donor‐acceptor type electronic structures. This work not only unmasks a new core‐shell interface involving cyanurate ligand but also underlines the significance of high‐electron‐affinity N‐heterocyclic ligand in synthesizing TADF metal nanoclusters. This is the first mixed valence Ag 0/I nanocluster with TADF characteristic.