Publications (2)14.76 Total impact
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Article: High yield synthesis of Au25 nanoclusters by controlling the reduction process.
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ABSTRACT: The syntheses of gold nanoclusters, namely, the 25-gold-atom nanocluster (Au25(SR)18) and 38-gold-atom nanocluster (Au38(SR)24), with SR representing the thiol ligand, were described in previously reported studies. The synthesis was via a fast reduction process using sodium borohydride. The ratio of Au:HSR:NaBH4 was 1:3:10. Herein we report that the Au25 nanocluster can also be synthesized via a slow reduction process through a dropwise addition of an aqueous solution of sodium borohydride. The ratio of Au:S:NaBH4 is also changed to 1:3:5. This method synthesized Au25 nanoclusters at a high yield (47%). Pure Au25 nanoclusters were obtained after extraction, and the product was fully characterized by UV-vis spectroscopy, thermogravimetric analysis (TGA) and Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry. The possible formation mechanism is discussed in this paper. This work contributes to a better understanding of the mechanism of Au25 formation and provides a basis for further study of gold nanoclusters.Journal of Nanoscience and Nanotechnology 02/2013; 13(2):1282-5. · 1.56 Impact Factor -
Article: Chiral Au₂₅ nanospheres and nanorods: synthesis and insight into the origin of chirality.
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ABSTRACT: Chirality in nanoparticles is an intriguing phenomenon. Herein, we have devised a well-defined gold nanoparticle system for investigating the origin of chirality in nanoparticles. We have designed chiral thiols (R- and S-isomers) and synthesized chiral gold nanoparticles composed of 25 gold atoms and 18 ligands, referred to as Au(25)(pet)(18), where pet represents chirally modified phenylethylthiolate -SCH(2)CH(CH(3))Ph at the 2-position. These optically active nanoparticles are close analogues of the optically nonactive phenylethylthioalte-capped Au(25)(pet)(18) nanoparticles, and the latter's crystal structure is known. On the basis of the atomic and electronic structures of these well-defined Au(25) nanoparticles, we have explicitly revealed that the ligands and surface gold atoms of Au(25)(pet)(18) play a critical role in effecting the circular dichroism responses from the nanoparticles. Similar effects are also observed in chiral Au(25) rods. The mixing of electronic states of ligands with those of surface gold atoms constitutes the fundamental origin of chirality in such nanoparticles.Nano Letters 08/2011; 11(9):3963-9. · 13.20 Impact Factor
