Exploring the functionalization of Ag ₂₀ nanoclusters through cluster surface tetrazine ligation

Controlled synthesis of atomically precise silver nanoclusters (AgNC) exhibits some challenges due to inferior stability and limited solubility of silver precursors, which impacts their applications. Generating strategies for post-synthesis cluster modification can help expand the current applications and promote the production of hybrid nanomaterials. This approach has recently been explored using Cluster-Surface (CS)-click chemistry; however, the types of CS-click reactions have been limited, mostly to alkyne-azide cycloaddition. The aim of this study is to expand the scope of post-synthesis cluster-surface click chemistries for AgNC by incorporating the inverse electron demand Diels–Alder reaction (IEDDA) as a strategy for cluster surface functionalization. Here, the synthesis and characterization of a carbonate templated Ag 20 NC, [(CO 3 )@Ag 20 (S t Bu) 10 ( exo-C 7 H 9 COO) 8 (DMF) 4 ] (1- n), which bears a norbornene moiety susceptible to functionalization through IEDDA is reported. This study shows the structure of the nanocluster obtained through single crystal X-ray diffraction and characterization of the clicked product after reaction with a model s-tetrazine. This work highlights the versatility of click chemistry and offers a new path for cluster-surface modification.