Au57 Ag53 (C≡CPh)40 Br12 : A Large Nanocluster with C1 Symmetry

Abstract

The controlled synthesis and structure determination of a bimetallic nanocluster Au₅₇ Ag₅₃ (C≡CPh)₄₀ Br₁₂ (Au₅₇ Ag₅₃ ) is presented. The metal core has a four-shell Au₂ M₃ @Au₃₄ @Ag₅₁ @Au₂₀ (M=1/3 Au+2/3 Ag) architecture. In contrast to the previously reported large nanoclusters that have highly symmetric kernel structures, the metal atoms in Au₅₇ Ag₅₃ are arranged in an irregular manner with C₁ symmetry. This cluster exhibits excellent thermal stability and is robust under oxidative or basic conditions. The silver precursors play a key role in dictating the structures of the nanoclusters, which suggests the importance of the counteranions used.

Keywords: alkynyl ligands; cluster compounds; gold; optical properties; silver.