What Determines If a Ligand Undergoes Coordination or Catalytic Activation on a Metal Cluster?

We report a joint experimental and theoretical study on the reactivity of Ag n + clusters with H 2 S, D 2 O, and NH 3 . Complete dehydrogenation products are observed for Ag n + reacting with H 2 S, but no dehydrogenation products are found for D 2 O or NH 3 under the same reaction condition. Theoretical calculations elucidate why Ag n + clusters show different reactivities with these inorganic hydrides. NH 3 shows strong coordination with Ag n + , but the dehydrogenation reactions are unfavorable; in contrast, the fragile H-S bonds and stable Ag n S + products facilitate the hydrogen evolution of H 2 S on Ag n + . We fully analyzed the metal-ligand interactions of Ag n + clusters with three molecules and illustrated the reaction dynamics and charge-transfer interactions and altered the superatomic states during the formation of cluster sulfides. We expect this study to benefit the design of stable environmentally friendly desulfurization catalysts and also the understanding of the mechanism on ligand-protected metal clusters in wet chemistry.