Metallophilicity-Driven Dynamic Aggregation of a Phosphorescent Gold(I)–Silver(I) Cluster Prepared by Solution-Based and Mechanochemical Approaches

We observed an unusual reversible aggregation process showing stimuli-responsive structural dynamics and optical changes attributed to the formation of a sandwich-like Au3-Ag-Au3 cluster, which can be synthesized through both solution and mechanochemical methods. Unlike many other heteronuclear gold-silver clusters, the affinity of two cyclic Au3 complexes and a Ag(I) ion is solely bound by ligand unsupported Au-Ag bonding. The assembly/disassembly behavior, further forming nanoaggregates, is controllable by adjusting the concentration of the solution. In the solid state, the insertion of Ag(I) ion can be implemented through a mechanochemical approach, accompanied by visual color changes and reversible luminochromism. Furthermore, an uncommon solid-liquid extraction is demonstrated, showing the uniqueness of this labile Au-Ag metallophilicity and hinting at the possibility of manipulating a bonding process through a heterogeneous route.