Related Experiment Video
Updated: Jul 10, 2026

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions
Published on: February 5, 2016
Gold nanoparticle-initiated free radical oxidations and halogen abstractions
Petre Ionita1, Marco Conte, Bruce C Gilbert
1Department of Chemistry, University of York, Heslington, York, UK YO10 5DD.
Abstract:
We report on the use of EPR spectroscopy and spin trapping technique to detect free radical intermediates formed in the presence of gold nanoparticles. Phosphine- and amine-protected gold nanoparticles were found to initiate air oxidation of organic substrates containing active hydrogen atoms, such as amines and phosphine oxides. Nanoparticles protected by stronger bound ligands (e.g., thiols) were inactive in these reactions. We also found that gold nanoparticles are able to abstract a halogen atom from the halogenated compounds, presumably due to the high affinity of gold metal for halogens. Reaction of Au nanoparticles with chloroform showed an unusual inverse isotope effect. The trichloromethyl spin adduct was observed when Au nanoparticles were mixed with CDCl(3) but not with CHCl(3). This unexpected behaviour suggests that C-H bond breaking is not the rate-determining step in Au-initiated hydrogen abstraction.
Related Concept Videos
Radical Formation: Abstraction
Even though homolysis produces radicals, it is different from radical...
Base-Promoted α-Halogenation of Aldehydes and Ketones
Radical Autoxidation
Radical Formation: Homolysis
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Radical Formation: Overview
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the latter, also known...

