Precision at the nanoscale: On the structure and property evolution of gold nanoclusters

Abstract

Chemists are often regarded as "architects", who are capable of building up complex molecular structures in the ultrasmall-dimensional world. However, compared with organic chemistry, nanochemistry - which deals with nanoparticles in the size range from 1 to 100 nm - is less precise in terms of synthesis, composition, and structure. Such an imprecise nature of nanochemistry has impeded an in-depth understanding as well as rational control of structures and properties of nanomaterials. Motivated by this, thiolate-protected gold nanoclusters (denoted as Aun(SR)m) have recently emerged as a paradigm of atomically precise nanomaterials, in which all the nanoparticles are identical to each other with the same number of core atoms (n) and surface ligands (m) as well as the atomic arrangement. In this review, we provide a demonstration of how the precise nature of Aun(SR)m nanoclusters allows one to understand, decipher and discover some important, enigmatic and intriguing issues and phenomena in nanoscience, including (i) a precise nanoscale transformation reaction induced by surface ligand exchange, (ii) the total structures of crystalline metal phases and the self-assembled surface monolayers, (iii) the periodicities and quantum confinement in nanoclusters and (iv) the emergence of hierarchical complexity in the entire nanoparticle system. We expect that such an in-depth understanding will eventually lead to the rational design and precise engineering of complex architectures at the nanoscale.