Process for making cyano functionalized gold nanoparticles

1. A method of making cyanide-functionalized gold nanoparticles, the method comprising:

forming an aqueous reaction mixture comprising a gold precursor and glycine,

keeping the reaction mixture at about 18° C. to about 50° C. for at least 6 days to provide formation of the cyanide-functionalized gold nanoparticles, and

isolating the cyanide-functionalized gold nanoparticles from the reaction mixture.

2. The method of claim 1 , wherein keeping the reaction mixture about 18° C. to about 50° C. for at least 6 days is done in the dark without stirring.

3. The method of claim 1 , wherein the gold precursor comprises K[AuCl 4 ], chloroauric acid, gold (III) chloride; gold (III) iodide, trichloro(pyridine)gold(III), chloro(triphenylphosphine)gold(I), gold(I) cyanide, gold(III) bromide, gold(I) sulfide, gold(III) hydroxide, chloro(triethylphosphine)gold(I), methyl(triphenylphosphine)gold(I), or a salt thereof.

4. The method of claim 1 , wherein the reaction mixture has a pH of about 7 to about 14.

5. The method of claim 1 , wherein the reaction mixture comprises 0.001 to 1 wt % of the gold precursor, and 0.001 to 1 wt % of the glycine, based on the weight of the reaction mixture.

6. The method of claim 1 , further comprising monitoring the formation of the cyanide-functionalized gold nanoparticles by UV-visible spectroscopy, dynamic light scattering particle analysis, Raman spectroscopy, or a combination comprising at least one of the foregoing.

7. The method of claim 1 , wherein the cyanide-functionalized gold nanoparticles have an average diameter of about 10 to about 200 nm.

8. The method of claim 1 , wherein the cyanide in the cyanide-functionalized gold nanoparticles covers about 0.1% to about 40% of the nanoparticle surface.