Metal–ligand interfaces for well-defined gold nanoclusters

Ligand engineering for well-defined gold nanoclusters(Au NCs) is getting more extensive attention. Organizing the Au-ligand interfaces on gold NCs can achieve the structural and functional control. This review focuses on the Au-ligand interfaces including gold-phosphorus(Au-P), gold-sulfur(Au-S), gold-selenium(Au-Se), gold-carbon(Au-C), and gold-nitrogen(Au-N), derived from the bonding between Au atoms and the different ligands(e.g., organic phosphine, thiolate, selenolate, alkynyl,n-heterocyclic carbene and nitrogenous ligands). The formation mechanism of Au-ligand interfaces is well discussed. In addition, the effects of Au-ligand interfaces on the stability, optical property, and catalysis are also presented. We hope the advances in this research area can boost the development of Au NC sciences.

Modulating the alloying mode in the doping-induced synthesis of Au-Pd nanowires

Heterogeneous doping is one effective strategy for synthesizing metal alloy nanowires.Herein,the heterogeneous doping processes of Pd on the ultrathin Au nanowires were systematically modulated and investigated.Au-Pd alloy nanowires with various morphologies and lattice structures can be obtained by adjusting the morphology of the precursor Au nanowires and the kinetics of the heterogeneous doping processes.The effects of the rate of Pd reduction and the concentration of the ligand oleylamine(OAm)on the Pd deposition and alloying mode were articulated.Generally,as the Pd deposition rate decreases,the Pd deposition and alloying mode switches from the island-forming Stransky–Krastanov(SK)mode to the epitaxial Frank-van der Merwe(FM)mode,and eventually to an unconventional twisting alloying mode,where the interdiffusion of Pd and Au causes drastic rearrangement of the lattice structure and formation of helical structures.The kinetics-related variation of alloying mode could also be observed in the Au-Ag nanowires,demonstrating a general design principle for the synthesis of alloy nanostructures.In addition,the electrocatalytic performance of various Au-Pd nanowires was evaluated,and the alloy nanowire formed via the SK mode was found to be an excellent electrocatalyst for oxygen reduction and ethanol oxidation.

Atomically Precise Water-Soluble Gold Nanoclusters:Synthesis and Biomedical Application

Atomically precise water-soluble gold nanoclusters(Au NCs)protected by organic ligands have attracted growing attention in serving as unique nanomaterials with the potential to generate theranostic tools(bioimaging,biosensing,and biotherapy),due to their ultrasmall size,superior photoluminescence,good biocompatibility,and nontoxicity.More importantly,Au NCs afford a well-defined atomic packing structure and molecular purity,providing a superior platform to unravel the structure−performance correlations for biodistribution,biological pharmacokinetics,and excretion of Au NCs.In this Review,we mainly survey the synthesis of water-soluble Au NCs and the recent progress in biomedicine of Au NCs,including bioimaging,biosensing,and biotherapy.The effects of ligand and size on the biomedical properties are discussed in detail.We hope that the advances in this research area can expand the applications of Au NCs in biomedicine.