A novel method for the synthesis of monodisperse gold-coated silica nanoparticles
Monodisperse silica nanoparticles were synthesised by the well-known Stober protocol, then dispersed in acetonitrile (ACN) and subsequently added to a bisacetonitrile gold(I) coordination complex ([Au(MeCN)2]?) in ACN. The silica hydroxyl groups were deprotonated in the presence of ACN, generating a formal negative charge on the siloxy groups. This allowed the [Au(MeCN)2]? complex to undergo ligand exchange with the silica nanoparticles and form a surface coordination complex with reduction to metallic gold (Au0) proceeding by an inner sphere mechanism. The residual [Au(MeCN)2]? complex was allowed to react with water, disproportionating into Au0 and Au(III), respectively, with the Au0 adding to the reduced gold already bound on the silica surface. The so-formed metallic gold seed surface was found to be suitable for the conventional reduction of Au(III) to Au0 by ascorbic acid (ASC). This process generated a thin and uniform gold coating on the silica nanoparticles. The silica NPs batches synthesised were in a size range from 45 to 460 nm. Of these silica NP batches, the size range from 400 to 480 nm were used for the gold-coating experiments.
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|Item Type:||Journal Article|
|Keywords:||Monodisperse silica nanoparticles, Gold-coated silica nanoparticles, Surface coordination complex, Gold-shell nanoparticles, Inner sphere mechanism, Composite gold colloid|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000)|
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering|
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2012 Springer|
|Copyright Statement:||The original publication is available at SpringerLink http://www.springerlink.com|
|Deposited On:||02 May 2012 14:35|
|Last Modified:||02 May 2012 14:52|
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