Date of Award

12-2009

Degree Name

Master of Science

Department

Chemistry

First Advisor

Dr. Sherine Obare

Second Advisor

Dr. Ekkehard Sinn

Third Advisor

Dr. Robert Ofoli

Access Setting

Masters Thesis-Campus Only

Abstract

A major challenge exists in the ability to synthesize well defined and monodisperse metallic nanoparticles in the 1 - 8 nm size range, where a high surfaceto- volume ratio and an increase in surface atom distribution greatly enhance the efficiency of catalytically active metals. Such nano-catalysts are essential for numerous important organic transformations. Here we report straightforward and reliable means of synthesizing palladium and ruthenium nanoparticles using a new class of organic stabilizing ligands: thioethers. Thioethers demonstrate a particular mastery at consistently controlling the sizes of the nanoparticles formed and their dispersity. Monodisperse ruthenium and palladium nanoparticles with mean diameters between 1.7 and 6.4 nm and 1.7 and 4.2 nm were synthesized, respectively. Thioether-stabilized palladium and ruthenium nanoparticles were characterized using transmission electron microscopy (TEM), UV-vis spectroscopy, powder X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). Schemes to immobilize these prepared nanoparticles on solid supports were also developed, producing heterogeneous catalysts. The catalytic activities of the prepared colloids and supported nanoparticles were evaluated in the hydrogenation of selected olefins. Gas chromatography-mass spectroscopy (GC-MS) showed high conversion percentages.

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