Abstract: In this article, a facile and rapid method was developed to synthesize intensely photoluminescent catalytic gold nanoclusters (AuNCs) based on etching small citrate-capped gold nanoparticles using 4,6-dimethyl-2-pyridineselenol-3-caronitrile and 4-Methylquinolineselenol- 3-carbonitrile as models for organoselenium compounds. The size and the catalytic performance of the prepared fluorescent nanoclusters were characterized using suitable Transmission Electron Microscope (TEM), Atomic Force Microscopy (AFM), Electrospray Ionization-Mass Spectrometry (ESI-MS) and photoluminescence techniques. It is shown that Au clusters with an average diameter of gold core 0.78 ± 0.41 nm (in the range of 5-9 atoms), have a catalytic role in the…show more content… In top-down techniques, clusters are synthesized from larger nanoparticles or bulk metal. Etching of nanoparticles using ligands (as thiols) is one of the most top-down techniques can be used for the synthesis of metal clusters. Removing the surface atoms or break the metal nanoparticles into smaller clusters by using the etching capacity of such ligands will lead to synthesize stable quantum clusters. For example, Habib et al. has used the etching of mercaptosuccinic acid protected gold nanoparticles with excess glutathione to yield small photoluminescent gold clusters either with 8 or 25 gold atoms . Polyethylenimine as multivalent coordinating polymers can also be used to etch preformed colloidal gold nanocrystals producing highly fluorescent nanoclusters . it is well confirmed that small noble metal nanoclusters display excellent catalytic activities such as aerobic oxidation of thiophenol , propene epoxidation, oxidation of styrene , p-nitrophenol reduction with NaBH4  and the reduction of methylene blue with hydrazine .
Organoselenium compounds are of considerable interest due to their wide efficiency and applicability with numerous therapeutic applications . In addition, the presence of a heterocyclic ring in these compounds upgrades their properties to a great