Aurophilic interactions (AuI⋅⋅⋅AuI) are crucial in directing the supramolecular self‐assembly of many gold(I) compounds; however, this intriguing chemistry has been rarely explored for the self‐assembly of nanoscale building blocks. Herein, we report on studies on aurophilic interactions in the structure‐directed self‐assembly of ultrasmall gold nanoparticles or nanoclusters (NCs, <2 nm) using [Au25(SR)18]− (SR=thiolate ligand) as a model cluster. The self‐assembly of NCs is initiated by surface‐motif reconstruction of [Au25(SR)18]− from short SR‐[AuI‐SR]2 units to long SR‐[AuI‐SR]x (x>2) staples accompanied by structure modification of the intrinsic Au13 kernel. Such motif reconstruction increases the content of AuI species in the protecting shell of Au NCs, providing the structural basis for directed aurophilic interactions, which promote the self‐assembly of Au NCs into well‐defined nanoribbons in solution. More interestingly, the compact structure and effective aurophilic interactions in the nanoribbons significantly enhance the luminescence intensity of Au NCs with an absolute quantum yield of 6.2 % at room temperature.

The design of surface ligands is crucial for ligand‐protected gold nanoclusters (Au NCs). Besides providing good protection for Au NCs, the surface ligands also play the following two important roles: i) as the outermost layer of Au NCs, the ligands will directly interact with the exterior environment (e.g., solvents, molecules and cells) influencing Au NCs in various applications; and ii) the interfacial chemistry between ligands and gold atoms can determine the structures, as well as the physical and chemical properties of Au NCs. A delicate ligand design in Au NCs (or other metal NCs) needs to consider the covalent bonds between ligands and gold atoms (e.g., gold–sulfur (Au–S) and gold–phosphorus (Au–P) bond), the physics forces between ligands (e.g., hydrophobic and van der Waals forces), and the ionic forces between the functional groups of ligands (e.g., carboxylic (COOH) and amine group (NH2)); which form the underlying chemistry and discussion focus of this review article. Here, detailed discussions on the effects of surface ligands (e.g., thiolate, phosphine, and alkynyl ligands; or hydrophobic and hydrophilic ligands) on the synthesis, structures, and properties of Au NCs; highlighting the design principles in the surface engineering of Au NCs for diverse emerging applications, are provided.

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We report an effective and universal approach for the preparation of ultrathin single- or multiple-component transition-metal hydroxide (TMH) nanosheets with thickness below 5 nm. The unique synthesis benefits from the gradual decomposition of the preformed metal-boron (M-B, M=Fe, Co, Ni, NiCo) composite nanospheres which facilitates the formation of ultrathin nanosheets by the oxidation of the metal and the simultaneous release of boron species. The high specific surface area of the sheets associated with their ultrathin nature promises a wide range of applications. For example, we demonstrate the remarkable adsorption ability of Pb(II) and As(V) in waste water by the ultrathin FeOOH nanosheets. More interestingly, the process can be extended simply to the synthesis of composite structures of metal alloy hollow shells encapsulated by TMH nanosheets, which show excellent catalytic activity in the Heck reaction.