[tt] [Hplusroadmap] Re: "Easy" synthesis of semiconductor nanoparticles (was: KurzweilAI.net Daily Newsletter)

Bryan Bishop <kanzure at gmail.com> on Fri Feb 29 23:44:16 UTC 2008

On Friday 29 February 2008, KurzweilAI.net wrote:
> *************************
> 'Green' method to make gold
> nanoparticles
> KurzweilAI.net Feb. 29, 2008
> *************************
> University of Missouri scientist
> Kattesh Katti has discovered how to
> make gold nanoparticles using gold
> salts, soybeans and water, an
> alternative to production methods
> using toxic chemicals. The new
> process could allow medical
> researchers to expand the use of
> gold nanoparticles for drug delivery
> and other purposes. University of...
> http://www.kurzweilai.net/email/newsRedirect.html?newsID=8089&m=37981

From the paper.
> Synthetic protocols for stabilizing AuNPs by labeling with the GA
> matrix were investigated to develop readily injectable nontoxic AuNP 
> constructs for in vivo administration. Simple mixing of an aqueous 
> solution of commercially available sodium tetrachloroaurate with an 
> aqueous solution of a nontoxic phosphino amino acid [P(CH2NHCH3COOH)
> 3;THPAL] reducing agent in the presence of a 0.2% aqueous solution of 
> GA resulted in an instantaneous reaction that produced GA-labeled 
> AuNPs in over 98% yield.       

Gold salt (AuCl4 is needed, was only able to find AuCl):
http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/481130

Buy this: sodium tetrachloroaurate,
http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/298174

Make a phosphino amino acid - see (or the links below):
http://www.uni-leipzig.de/chemie/hh/downloads/artikel/121_Phos%20Sulf%20177%202002%201469-1471.pdf

You need to make THPAL, so see:
 K. Raghuraman, K. K. Katti, L. J. Barbour, N. Pillarsetty, C. L.
 Barnes, K. V. Katti, J. Am. Chem. Soc. 2003, 125, 6955 – 6961.

Abstract:
> Abstract: Phosphorus functionalized trimeric alanine compounds (L)-
> and (D)-P(CH2NHCH(CH3)COOH)3 2 are prepared in 90% yields by the 
> Mannich reaction of Tris(hydroxymethyl)phosphine 1 with (L)- or (D)- 
> Alanine in aqueous media. The hydration properties of (L)-2 and (D)-2 
> in water and water-methanol mixtures are described. The crystal 
> structure analysis of (L)-2‚4H2O, reveals that the alanine molecules 
> pack to form two-dimensional bilayers running parallel to (001). The 
> layered structural motif depicts two closely packed monolayers of 2 
> each oriented with its phosphorus atoms projected at the center of the 
> bilayer and adjacent monolayers are held together by hydrogen bonds 
> between amine and carboxylate groups. The water bilayers are 
> juxtaposed with the H-bonded alanine trimers leading to 18-membered 
> (H2O)18 water rings. Exposure of aqueous solution of (L)-2 and (D)-2 
> to methanol vapors resulted in closely packed (L)-2 and (D)-2 solvated 
> with mixed water-methanol (H2O)15(CH3OH)3 clusters. The O-O distances 
> in the mixed methanol-water clusters of (L)-2‚3H2O‚CH3OH and (D)-2
> ‚3H2O‚CH3OH (O-O(average) ) 2.857 Å) are nearly identical to the O-O 
> distance observed in the supramolecular (H2O)18 water structure 
> (O-O(average) ) 2.859 Å) implying the retention of the hydrogen bonded 
> structure in water despite the accommodation of hydrophobic methanol 
> groups within the supramolecular (H2O)15(CH3OH)3 framework. The O-O 
> distances in (L)-2‚3H2O‚CH3OH and (D)-2‚3H2O‚CH3OH and in (H2O)18 are 
> very close to the O-O distance reported for liquid water (2.85 Å). 
>
> Synthesis and Characterization of (L)-2 and (D)-2. As part
> of our continued efforts in the design and development of cancer 
> diagnostic and therapeutic agents,29,30 we have recently devel- 
> oped new strategies for the preparation of peptide-mimetic 
> dimeric and trimeric amino acid conjugates.31 Phosphorus 
> functionalized trimeric amino acid (L)-(HOOCCH(CH3)NHCH2)3P 
> (2) and (D)-(HOOCCH(CH3)NHCH2)3P (2) were prepared by 
> the addition of tris(hydroxymethyl phosphine) 1 to 3-fold excess 
> of (L)- or (D)-alanine, via a Mannich-reaction pathway, in water 
> in 90% yields (Scheme 1). Compounds (L)-2 and (D)-2 are white, 
> air-stable, crystalline compounds and are readily soluble in 
> water. The 31P{1H} NMR spectra of (L)-2 and (D)-2 in D2O 
> showed sharp singlets at δ -39.9 ppm. The 1H and 13C NMR 
> spectra of (L)-2 and (D)-2 in D2O are consistent with the 
> structure. The mass spectrum of (L)-2 showed a molecular ion 
> [M+H+] peak with m/z ) 338.0 consistent with the formula 
> weight (337.31). 

Ref #31 is:  Berning, D. E.; Katti, K. V.; Barnes, C. L.; Volkert, W. A. 
J. Am. Chem. Soc. 1999, 121, 1658-1664.

Re: Mannich-reaction pathways, see:
http://www.organic-chemistry.org/namedreactions/mannich-reaction.shtm
http://en.wikipedia.org/wiki/Mannich_reaction

For the tris(hydroxymethyl phosphine):
http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/177881

(D)-alanine
http://www.sigmaaldrich.com/catalog/search/ProductDetail/FLUKA/05140

and then a 0.2% aqueous solution of "gum arabic" (the plant). Katti 
claims it's an instantaneous reaction that immediately results in the 
nanoparticles.

You can get the papers at:
http://heybryan.org/projects/eznanoparticles/

Best get it done.
- Bryan
________________________________________
Bryan Bishop
http://heybryan.org/

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