Abstract
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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andreescu D, Sau TK, Goia DV (2006) Stabilizer-free nanosized gold sols. J Colloid Interface Sci 298:742–751. doi:10.1016/j.jcis.2006.01.011
Bergerhoff G (1964) Preparation of copper(I) and gold(I) compounds in acetonitrile. Zeitschrift fuer Anorganische und Allgemeine Chemie 327:139–142
Goia DV, Matijevic E (1998) Preparation of monodispersed metal particles. New J Chem 22:1203–1215
Hasan M, Bethell D, Brust M (2002) The fate of sulfur-bound hydrogen on formation of self-assembled thiol monolayers on gold: 1H NMR spectroscopic evidence from solutions of gold clusters. J Am Chem Soc 124:1132–1133. doi:10.1021/ja0120577
Hiramatsu H, Osterloh FE (2003) pH-controlled assembly and disassembly of electrostatically linked CdSe–SiO2 and Au–SiO2 nanoparticle clusters. Langmuir 19:7003–7011. doi:10.1021/la034217t
Hu K-W, Jhang F-Y, Su C-H, Yeh C-S (2009) Fabrication of Gd2O(CO3)2·H2O/silica/gold hybrid particles as a bifunctional agent for MR imaging and photothermal destruction of cancer cells. J Mater Chem 19:2147–2153. doi:10.1039/B815087G
Johnson PR, Pratt JM, Tilley RI (1978) Experimental determination of the standard reduction potential of the gold(I) ion. J C S Chem Commun 14:606–607. doi:10.1039/C39780000606
Kim J-H, Chung H-W, Lee TR (2006) Preparation and characterization of palladium shells with gold and silica cores. Chem Mater 18:4115–4120. doi:10.1021/cm0528882
Qu Q, Peng S, Mangelings D, Hu X, Yan C (2010) Silica spheres coated with C18-modified gold nanoparticles for capillary LC and pressurized CEC separations. Electrophoresis 31:556–562. doi:10.1002/elps.200900375
Rao KS, El-Hami K, Kodaki T, Matsushige K, Makino K (2005) A novel method for synthesis of silica nanoparticles. J Colloid Interface Sci 289:125–131. doi:10.1016/j.jcis.2005.02.019
Ruff I (1968) Extension of the “band model” to the inner-sphere mechanism of electron-transfer reactions. J Phys Chem 72:1792–1797. doi:10.1021/j100851a071
Salgueiriño-Maceira V, Correa-Duarte MA, Farle M, López-Quintela A, Sieradzki K, Diaz R (2006) Bifunctional gold-coated magnetic silica spheres. Chem Mater 18:2701–2706. doi:10.1021/cm0603001
Shi Y-L, Asefa T (2007) Tailored core–shell–shell nanostructures: sandwiching gold nanoparticles between silica cores and tunable silica shells. Langmuir 23:9455–9462. doi:10.1021/la700863g
Stathis EC, Fabrikanos A (1958) Preparation of colloidal gold. Chem Ind 27:860–861
Stöber W, Fink A, Bohn E (1968) Controlled growth of monodisperse silica spheres in the micron size range. J Colloid Interface Sci 26:62–69. doi:10.1016/0021-9797(68)90272-5
Taube H, Myers H, Rich RL (1953) Observations on the mechanism of electron transfer in solution. J Am Chem Soc 75:4118–4119. doi:10.1021/ja01112a546
Turkevich J, Stevenson PC, Hillier J (1953) The formation of colloidal gold. J Phys Chem 57:670–673. doi:10.1021/j150508a015
Turner M, Golovko VB, Vaughan OPH, Abdulkin P, Berenguer-Murcia A, Tikhov MS et al (2008) Selective oxidation with dioxygen by gold nanoparticle catalysts derived from 55-atom clusters. Nature 454:981–983. doi:10.1038/nature07194
Ueda A, Haruta M (1999) Nitric oxide reduction with hydrogen, carbon monoxide, and hydrocarbons over gold catalysts. Gold Bull 32:3–11
Wang W, Ruan C, Gu B (2006) Development of gold-silica composite nanoparticle substrates for perchlorate detection by surface-enhanced Raman spectroscopy. Anal Chim Acta 567:121–126. doi:10.1016/j.aca.2006.01.083
White IM, Oveys H, Fan X (2006) Increasing the enhancement of SERS with dielectric microsphere resonators. Spectroscopy 21(36):38–42
Williams DH, Fleming I (1995) Spectroscopic methods in organic chemistry, 5th edn. McGraw-Hill, Berkshire, p 69
Acknowledgments
The authors wish to thank Dr. Loc Duong and Jin Chang for assistance with SEM imaging, Mr. Lambert Bekessy and Jin Chang for assistance with TEM images and Dr. Mark Wellard for assistance with 1H NMR along with Dr. Chris Cavallo for assistance with obtaining mass spectra and the School of Chemical and Physical Sciences of QUT for project support.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
English, M.D., Waclawik, E.R. A novel method for the synthesis of monodisperse gold-coated silica nanoparticles. J Nanopart Res 14, 650 (2012). https://doi.org/10.1007/s11051-011-0650-2
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s11051-011-0650-2