Reactivity of Silver Clusters Anions with Ethanethiol

We have investigated the gas-phase reactivity of silver clusters with ethanethiol in a fast-flow tube reactor. The primary cluster products observed in this reaction are Ag_nSH^– and Ag_nSH₂^–, indicating C–S bond activation, together with interesting byproducts H₃S^– and (H₃S)₂^–. Ag_n^– clusters with an odd number of valence electrons (n = even) were observed to be more reactive than those with an even number of electronsa feature previously only observed in the reactivity of Ag_n^– with triplet oxygen, indicating that radical active sites play a role in their reactivity. Furthermore, the reactivity dramatically increases with large flow rate of ethanethiol being introduced in the flow tube. Theoretical investigations on the reactivity of Ag₁₃^– and Ag₈^– with ethanethiol indicate that both Ag₁₃^– and Ag₈^– face significant barriers to reactivity with a single ethanethiol molecule. However, Ag₈^– reacts readily in a cooperative reaction with two ethanethiol molecules, consistent with the dramatic increase in reactivity with a large flow rate. Further hydrogen-transfer reactions may then release an ethylene molecule or an ethyl radical resulting in the observed Ag_nSH^– species.