ORGN 298 |
| Eric A. Noe, Judge Brown II, and Diwakar M Pawar. Department of Chemistry, Jackson State University, 1400 J. R. Lynch Street, Jackson, MS 39217-0510 |
| The carbon-13 spectrum for a mixture of cis - and trans - cycloundecenes shows two peaks at -50 C (dial) for the olefinic carbons, with the cis isomer (minor) absorbing upfield of the trans (major). The cis olefinic carbon peak splits into two peaks of equal intensity by - 160 degrees (dial), indicating that a single conformation of C1 symmetry is present. The olefinic carbon peak for the trans isomer broadens slightly around - 100 degrees (dial) and then sharpens. This effect is much more pronounced for some of the CH2 carbons (e.g., the peak at 36.4 ppm), and indicates the presence of at least one more conformation, of low population. Separation of the isomers and taking individual spectra is in progress. Free energies of possible conformations have been obtained from MM3 and Hartree-Fock ab initio calculations. |
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Physical Organic, Combinatorial, Materials, Molecular Recognition
8:00 PM-10:00 PM, Tuesday, March 30, 2004 Anaheim Convention Center -- Hall A, Poster
Division of Organic Chemistry |