FLUO 6 |
| Our group has had a long-standing interest in fluorous chemistry. Fluorous substances are fluorine-rich, and based upon sp3-hybridized carbon. They are both lipophobic and hydrophobic, and hence useful for multiphase catalysis. This presentation will highlight several new directions involving fluorocarbon phases and microenvironments for catalyst recovery and activation. One will exploit fluoropolymer solid phases such as various forms of PTFE as vehicles for catalyst recovery. Another will focus on fluorous liquid phases for catalyst activation. For example, there are many metal-based catalyst precursors from which a ligand must first dissociate before the catalytic cycle can be entered. The reverse reaction often slows the overall rate. Thus, an efficient ligand scavenging protocol could give faster reactions. Accordingly, derivatives of Grubbs' second generation catalyst with fluorous phosphines have been prepared, and under organic/fluorous liquid/liquid biphase systems significant rate accelerations are observed. Finally, it is sometimes desirable to effect catalysis in fluorous media. The synthesis of fluorous phosphonium salts and their use as phase transfer catalysts for ionic displacements in extremely non-polar fluorous solvents will be detailed. Recent lead reference: da Costa, R. C.; Gladysz, J. A. Adv. Synth. Catal. 2007, 349, 243-254. |
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Nanostructured Fluorocarbons: Smart Tectons for Self-Assembly
12:00 PM-5:05 PM, Sunday, August 19, 2007 BCEC -- 252B, Oral
Division of Fluorine Chemistry |