Reactivity of Au25 clusters with Au3+

Abstract

We report the instantaneous decomposition of the small molecular gold cluster, Au 25 SG 18 (SG-glutathione thiolate) in the presence of externally added chloroaurate ions resulting in the instantaneous formation of the insoluble gold-glutathione polymer. The rate of decomposition, however, was much slower for the metal ions such as Ag + , Fe 3+ , Cu 2+ , Ni 2+ , Cd 2+ , Zn 2+ and Sr 2+ . This chemical reactivity is shown to have no direct correlation with the electrochemical potential of the added ions.

Bright, NIR‐Emitting Au23 from Au25: Characterization and Applications Including Biolabeling

“…Etching of gold nanoparticles by excess thiols is known. [12][13][14][15]20] During interfacial etching at 25 8C, octanethiol etches Au 25 at the water-toluene interface and the etched gold atoms along with some glutathione ligands form Au I SG thiolate, which precipitates. The removal of some of the gold atoms from the Au 25 core changes the core and a new cluster is formed.…”

“…Synthesis of Au 25 SG 18 : Au 25 SG 18 was synthesized from the as-prepared Au@SG clusters by ligand etching. [12][13][14][15] The as-prepared Au@SG cluster was dissolved in water (25 mL). GSH was added (614 mg) and stirred at 55 8C.…”

“…Synthesis of novel nanomaterials with distinct physical and chemical properties continues to draw wide attention from researchers. Subnanoclusters, or molecular clusters of noble metals, especially of silver [1][2][3][4] and gold, [5][6][7][8][9][10][11][12][13][14][15][16] are new materials with numerous possibilities. They are composed of very few atoms, with a core size in the subnanometer regime, and are very different from the metallic nanoparticles of the same element.…”

“…The inherent fluorescence of Au 23 was used for imaging human hepatoma cells by employing the avidin-biotin interaction. Keywords: core etching · fluorescence · gold · nanostructures · phase transfer Whereas, the smaller analogues such as Au 5 , Au 8 , and Au 13 , synthesized inside dendrimer cavities, are highly fluorescent with a quantum yield ranging from 0.1-0.7 (10-70 %). [5] Since subnanoclusters are highly fluorescent and biocompatible due to the lower metallic content, they hold great promise as ultrabright, biocompatible biolabels and light-emitting sources in nanoscale, and hence can be used in imaging, detection, and so on, in conjunction with therapeutics.…”

Facile synthesis of biocompatible gold nanoparticles from Vites vinefera and its cellular internalization against HBL-100 cells

“…Gold nanoparticles can be stabilized by anionic ligands such as carboxylic acid derivatives like citrate, tartrate, and lipoic acid (Peng et al 2007). Earlier studies showed that glutathione used for capping gold quantum clusters (AU-n-SG-m) (−SG, glutathione thiolate) is one such group of compounds which has been well known for the stability of the AUNPs synthesized chemically (Habeeb and Pradeep 2007). Moreover, he confirmed in his results that the bigger clusters, n  > 25, can be converted into AU25SG18 by adding excess GSH.…”