Phosphine-stabilized gold nanoparticles have a rich chemistry and are excellent building blocks for functional groups, however they have typically been synthesized through cumbersome and unsafe methods. This process is a safer, more convenient, and more versatile procedure to synthesize small, phosphine-stabilized gold nanoparticles under ambient conditions.
Weare WW, Reed SM, Warner MG, Hutchinson JE
Department of Chemistry and Materials Science Institute, University of Oregon
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Dissolve hydorgen tetrachloroaurate trihydrate (1.00 g, 2.554 mmol) and tetraoctylammonium bromide (1.60 g, 2.93 mmol) in nitrogen sparged water/toulene misture (50 mL/65 mL).
After golden color transfers to organic phase, add triphenylphosphine (2.32 g, 8.85 mmol) to the solution and stir vigorously for 10 min until phase is white and cloudy.
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Add aqueous sodium borohydride (1.41 g, 37.3 mmol, dissolved in 10 mL of water immediately prior to use) to solution. Organic phase will immediately turn dark purple.
Stir for 3 hours under nitrogen.
Separate toluene layer and wash with water (2 x 100 mL). Remove solvent in vacuo or with nitrogen stream, yielding a black solid.
Wash resulting solid with solvents (hexanes, saturated aqueous sodium nitrite, and 2:3 methanol:water mixture) to remove phase transfer catalyst, byproducts, and unreacted starting materials.
Purify by precipitation from chloroform and pentane.
Process yields 170 mg of purified nanoparticle from 1 g of HAuCl4.
- hydrogen tetrachloroaurate trihydrate
- tetraoctylammonium bromide
- triphenylphosphine
- sodium borohydride