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
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.
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
- sodium borohydride