Reduction-Oxidation Cascade Strategy for Reforming a Au13-Kerneled Gold Thiolate Nanocluster.

ABSTRACT

Gold nanoclusters protected by thiolate ligands are ideal models for investigating the structure-property correlation of nanomaterals. Introducing relatively weak coordinating ligands into gold thiolate nanoclusters and thus reforming their structures is beneficial for further releasing their activities. However, controlling the selectivity of the process is a challenging task. In this work, we report a cascade strategy for deeply and purposefully reforming the structures of gold thiolate nanoclusters, exemplified by a Au13-kerneled Au23 nanocluster. Specifically, weakly coordinated triphenylphosphine was utilized to reduce (activate) the surface of Au23, enabling its further structural reformation by the following oxidation step. A structurally distinctive Au20 nanocluster was obtained based on this reduction-oxidation cascade strategy. Mechanism studies reveal that both the reduction and oxidation steps and their working sequence are critical for the transformation. Theoretical and experimental results all indicate that the deep structural reformation results in the evolution of the electronic and photoluminescent properties of the gold thiolate nanocluster.