Atomically Precise Metal Nanoclusters: Novel Building Blocks for Hierarchical Structures.

Atomically precise ligand-protected nanoclusters (NCs) constitute an important class of compounds that exhibit well-defined structures and, when sufficiently small, evident molecular properties. NCs provide versatile building blocks to fabricate hierarchical superstructures. The assembly of NCs indeed offers opportunities to devise new materials with given structures and able to carry out specific functions. In this Concept article, we highlight the possibilities offered by NCs in which the physicochemical properties are controlled by the introduction of foreign metal atoms and/or modification of the composition of the capping monolayer with functional ligands. Different approaches to assemble NCs into dimers and higher hierarchy structures and the corresponding changes in physicochemical properties are also described.