COLL 295 |
| Yang Song, Victoria Jimenez, and Royce W. Murray. Kenan Laboratories of Chemistry, University of North Carolina at Chapel Hill, University of North Carolina at Chapel Hill, CB#3290, Chapel Hill, NC 27599-3290 |
| Presented in this paper first is improved reversed-phase HPLC chromatographic separations of Au140 hexanethiolate monolayer protected nanoclusters (abbr. MPCs) and Au38 hexanethiolate MPCs, detected electrochemically (ECLC) by both a thin-layer macroelectrode flow cell and a fast-scan microelectrode detector. Discrete double-layer charging peaks were detected for the nanoparticles with resolution similar to that of the photodiode array detector (PDA). Based upon relative values of optical absorbance obtained from the PDA detector and current from both electrochemical detectors, the nanoparticle core sizes at various retention times were determined. Striking results show that some separated nanoparticles, eluting at significantly different chromatographic retention times, are apparently very similar in core sizes, which suggest subtle differences in ligand distribution on the surface of gold MPCs. Next, 13C NMR was utilized to probe the detailed ligand structure on gold nanoparticles, and NMR spectra of both monodispersed Au38 and Au140 MPCs show unexpected, fine structures, which are believed to correspond to ligands bound to different binding sites on cluster core surfaces. |
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Nanoscience and Nanotechnology
6:00 PM-8:00 PM, Monday, March 29, 2004 Disneyland -- North Exhibit Hall, Poster
Division of Colloid and Surface Chemistry |