ORGN 193 |
| This project was initiated to develop an effective receptor for perfluorooctanesulfonate (PFOS), an anionic surfactant that has gained notoriety as a globally-dispersed pollutant. Fluorous host 2 and hydrocarbon control 1 were prepared by attaching nonanoic acids to Anslyn's 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene scaffold. At low concentrations (< 0.0005 M) in CDCl3, the NH resonances of 1 and 2 appear at 5.22 and 5.28 ppm, respectively. Binding strengths with tetraethylammonium salts were determined by 1H NMR titrations in CDCl3. For PFOS, CF3SO3-, and Cl-, weak 1:1 binding (Kassoc < 50 M-1) was observed for 1. The fluorinated arms in 2 enhance affinity for chloride (Kassoc = 1500 M-1), while complexes of 2 with PFOS and CF3SO3- display higher-order stoichiometry. High-level calculations indicate that the reversal of molecular dipole associated with polyfluorination creates microdomains within 2 that favor salt binding.
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Total Synthesis, Materials, Devices and Switches, Molecular Recognition and Self-Assembly, Biologically-Related Molecules and Processes
8:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Sci-Mix
Division of Organic Chemistry |
