Atom-precise copper nanoclusters based on FCC, BCC, and HCP structures

In the past decades, coinage nanoclusters (NCs) have attracted much interest for their well-defined structures, intriguing properties, and various applications. With the development of efficient synthetic strategies and refined theoretical methods, numerous Au/Ag NCs with aesthetic structures have been isolated and their properties explored. In contrast, the chemistry of Cu NCs is relatively less developed, partly due to their intrinsic instability. In this regard, though some achievements have been made, there is a lack of systematic or in-depth discussion on the design, formation, and structure evolution of Cu NCs. In this review, we summarize the recently reported atomically precise Cu NCs, broadly categorized in terms of the three common crystalline phases, namely, facecentered-cubic (fcc), hexagonal-close-packing (hcp), and body-centered-cubic (bcc). Emphasis is focused on analysis of their metal core structures. It is hoped that this review will stimulate more research in the area of atom-precise CuNCs, thereby building up the materials base for nanoscience and nanotechnology.