Novel chloride-centered Ag18 clusters featuring a cuboctahedral Ag12 skeleton

Abstract

Two novel chloride-centered Ag₁₈ clusters with the same framework but different supporting phosphines are synthesized by the reaction of PhCCAg, AgSbF₆, PPh₃ (or P(p-Tol)₃), and NaBH₄ in CH₂Cl₂, followed by the addition of PhCCH and NEt₃. The inner twelve Ag atoms of these two clusters are arranged in a rare cuboctahedral structure, which can be rationalized by considering a ligand effect. Through careful analysis, we find that the central chloride arises from a generally ignored but nonetheless existing reaction between CH₂Cl₂ and NEt₃, which is well recognized as the Menshutkin reaction. This research provides insights into the dependence of the cluster structure on the nature of the ligand and into the cluster formation mechanism of the Menshutkin reaction.