Synthesis of Highly Fluorescent Metal (Ag, Au, Pt, and Cu) Nanoclusters by Electrostatically Induced Reversible Phase Transfer

Abstract

This paper reports a simple and scalable method for the synthesis of highly fluorescent Ag, Au, Pt, and Cu nanoclusters (NCs) based on a mild etching environment made possible by phase transfer via electrostatic interactions. Using Ag as a model metal, a simple and fast (total synthesis time < 3 h) phase transfer cycle (aqueous → organic (2 h incubation) → aqueous) has been developed to process originally polydisperse, nonfluorescent, and unstable Ag NCs into monodisperse, highly fluorescent, and extremely stable Ag NCs in the same phase (aqueous) and protected by the same thiol ligand. The synthetic protocol was successfully extended to fabricate highly fluorescent Ag NCs protected by custom-designed peptides with desired functionalities (e.g., carboxyl, hydroxyl, and amine). The facile synthetic method developed in this study should largely contribute to the practical applications of this new class of fluorescence probes.

Green Route to Prepare Biocompatible and Near Infrared Thiolate-Protected Copper Nanoclusters for Cellular Imaging

“…In the present study, the Cu 2p 3=2 band is observed at 932.3 eV (see Fig. S2), which is assigned to Cu(0), 41 and a weak peak can be observed at 942 eV, suggesting very minimal presence of Cu(II) in the system. 42 It is also worth mentioning that the binding energy di®erence between Cu(0) and Cu(I) is only $0.1 eV.…”

On the selection and design of proteins and peptide derivatives for the production of photoluminescent, red-emitting gold quantum clusters

“…Cysteine might be essential in cluster formation due to the electron withdrawing effect of the thiol-gold bond, which plays a crucial role in cluster stabilization [44]. If CCWE 6 R 3 was used as a reactant, addition of 1 molar equivalent of free tyrosine or MMYE 6 (Ac-Cys)]-GnRH-I, and their disulfide dimers indicated that the position of Cys residues is a crucial factor in AuQC production. There was no difference in cluster formation using acetylated or nonacetylated versions of GnRH-I derivatives.…”

“…A main strategy for preparation is a top-down approach in which gold clusters are prepared by controlled etching of monolayer-protected gold nanoparticles [5][6][7][8]. A ligand exchange-based reaction has also been reported [9].…”

Single Crystal Sub‐Nanometer Sized Cu6(SR)6 Clusters: Structure, Photophysical Properties, and Electrochemical Sensing

“…Due to the atomically precise composition and determined atom packing structure, thiolate‐stabilized metal nanoclusters have become an ideal system for studying the structure and size‐dependent properties of metal particles. Similarly, these systems have shown some very interesting quantum size effect and core size‐dependent optical and electronic properties 2. Among those studied, most research has been focused on thiol‐stabilized gold and silver nanoclusters (sometimes referred to as monolayer protected nanoclusters).…”