Mechanistic Elucidation of the Structure and Reactivity of Bare and Hydride-Protected Ag 17 + Clusters

We report an approach to create bare silver cluster Ag17+ and hydride-rich Ag17H14+ separately, as pure species uncontaminated with other entities, in the gas phase starting from a solution-phase monolayer-protected cluster, Ag18H16(PPh3)102+. These clusters can be synthesized just by applying a small potential on the cone of the mass spectrometer, during electrospray mass spectral analysis. Both the clusters were trapped and reacted with reactive gases like carbon monoxide and acetylene. Unusual products like Ag17(CO)7+ were observed when Ag17+ was reacted with CO in the trap. No intermediate species were found. Transfer of H from acetylene to the cluster during reaction was observed, which later reduced acetylene. All of the structures formed were calculated using density functional theory and show interesting facts about the composition of the products and the mechanism of their formation. Most of the structures were observed for the first time.