AEI 37 |
| Metal nanoparticles exhibit specific catalytic, electrochemical, photophysical properties depending on their size. Specifically the evolution of size dependent properties of gold nanoparticles has been of great interest. The choice of ligand plays a major role in the properties of nanoparticles. Fluorinated thiolate ligands may lead to interesting organization of nanoparticles due to their hydrophobic nature, low surface tension and immiscibility with common organic solvents(1,2,3 ) We have shown two routes to synthesize F-MPC's: 1) ligand exchange reaction with Au55(PPh3)Cl6 2) modified Brust synthesis using fluorinated thiols Perfluorobenzene thiol was ligand exchanged with Au55(PPh3)Cl6 to yield fluorinated nanoparticles, Au75(SC6F5)32 with minimal PPh3 impurity. Electrochemical and optical behaviour of these polydisperse nanoparticles are quite similar to the Au75(SC6)40. Modified Brust synthesis(5) was done using 1H, 1H, 2H, 2H - perfluorodecanethiol. Fluorinated MPC's by this route are not soluble in common organic solvents like toluene and CH2Cl2 and are soluble in fluorinated solvents. MALDI-MS reveals a mixture of ~44 atoms and ~75 atoms species. UV-Vis spectra of these particles featureless decay characteristic of <2nm and polydisperse particles. Further supportive TGA, NMR, XPS data are presented(4). This project has been supported by grants from the NSF. References: 1. Barriet, D; Lee, T.R. Curr. Opin. Colloid Interface Sci. 2003, 8, 236-242. 2. Yonezawa, T; Onoue, S.; Kimizuka, N. Langmuir, 2001, 17, 2291-2293. 3. Esumi, K; Sarashina, S; Yoshimura, T; Langmuir, 2004, 20, 5189-5191. 4. Dass, A; Guo, R; Balasubramanian, R.; Tracy, J.; Douglas, A.; Murray, R. W; manuscript in preparation. 5. Price, R. C.; Whetten, R. L. J. Am. Chem. Soc., 2005, 127, 13750-13751. |
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Academic Employment Initiative
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix
Academic Employment Initiative |