Multi-ligand-directed synthesis of chiral silver nanoclusters

Engineering the surface ligands of metal nanoclusters is critical for tuning their sizes, structures and properties at the atomic level. Herein, we report the synthesis and total structure determination of [Ag₃₂(Dppm)₅(SAdm)₁₃Cl₈]³⁺ and [Ag₄₅(Dppm)₄(S-Bu^t)₁₆Br₁₂]³⁺ (where Dppm = bis(diphenyphosphino)methane, HSAdm = 1-adamantanethiol and HS-Bu^t = tert-butyl mercaptan). The compositions of these two silver nanoclusters are determined by single-crystal X-ray diffraction (SC-XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Remarkably, the asymmetric distribution of the three types of ligands (thiolate, phosphine, and halogen) on the cluster surface is responsible for the chirality of the clusters. It is worth noting that these findings demonstrate the key principles of ligand-shell anchoring for the tri-ligand protected silver clusters. Our work will offer further insights into the synthesis of chiral metal clusters by tailoring the surface ligands.