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lab1 reference - J CHEM SOC CHEM COMMUN 1994 801 Synthesis...

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J. CHEM. SOC., CHEM. COMMUN., 1994 801 Synthesis of Thiol-derivatised Gold Nanoparticles in a Two-phase Liquid-Liquid System Mathias Brust, Merry1 Walker, Donald Bethell, David J. Schiffrin and Robin Whyman Department of Chemistry, The University of Liverpool, PO Box 147, Liverpool, UK L69 3BX Using two-phase (water-toluene) reduction of AuC14- by sodium borohydride in the presence of an alkanethiol, solutions 1-3 nm gold particles bearing a surface coating of thiol have been prepared and characterised; this novel material can be handled as a simple chemical compound. Colloidal solutions of metals have been known for a long time1 and a large variety of preparative techniques is now avail- able .2,3 Depending on the preparative conditions, the parti- cles have a tendency to agglomerate slowly, eventually lose their disperse character and flocculate. The removal of the solvent generally leads to the complete loss of the ability to reform a colloidal solution. Preparation of colloidal metals in a two-phase system was introduced by Faraday,4 who reduced an aqueous gold salt with phosphorus in carbon disulfide and obtained a ruby coloured aqueous solution of dispersed gold particles. Combining this two-phase approach with the more recent techniques of ion extraction and monolayer self- assembly with alkane thiols,s a one-step method for the preparation of an unusual new metallic material of derivatised nanometre-sized gold particles is described. The strategy followed consisted in growing the metallic clusters with the simultaneous attachment of self-assembled thiol monolayers on the growing nuclei. In order to allow the surface reaction to take place during metal nucleation and growth, the particles were grown in a two-phase system. Two- phase redox reactions can be carried out by an appropriate choice of redox reagents present in the adjoining phases.6 In the present case, AuC14- was transferred from aqueous solution to toluene using tetraoctylammonium bromide as the phase-transfer reagent and reduced with aqueous sodium borohydride in the presence of dodecanethiol (C12H2sSH).
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This note was uploaded on 03/30/2009 for the course BME 540 taught by Professor Gracias during the Spring '09 term at Johns Hopkins.

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lab1 reference - J CHEM SOC CHEM COMMUN 1994 801 Synthesis...

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