Solvent-induced reversible transformation between monomer-Ag32 and dimer-(Ag32)2 nanoclusters

The controllable transformation of metal nanoclusters remains highly desirable for the preparation of new clusters with novel structures and the elucidation of cluster conversion mechanisms. Here, we present the reversible transformation between two high-nuclearity silver cluster homologs, Ag32S3(StBu)16(CF3COO)9(CH3CN)4(NO3) (abbreviated as monomer-Ag32) and [Ag32S3(StBu)16(CF3COO)9(CH3CN)(NO3)]2 (abbreviated as dimer-(Ag32)2). Triggered by the solvent effect, the reversible conversion between monomer-Ag32 and dimer-(Ag32)2 nanoclusters has been accomplished. For dimer-(Ag32)2, two CF3COO− linkers were bound onto the symmetrical edges of adjacent Ag32 subunits, giving rise to the dimeric existence form of the final cluster. The optical properties, including optical absorptions and emissions, of the cluster monomer and dimer were then compared. This work offered an interesting case for constructing self-assembled cluster structures with the assistance of certain solvents and multidentate ligands.