ORGN 408 |
| M Squillacote and Fengting Liang. Department of Chemistry, Auburn University, 179 Chemistry Building, Auburn, AL 36849 |
| While the more stable conformation of most acyclic 1,3-butadienes is s-trans, much of the chemistry of 1,3-dienes proceeds through the less stable s-cis conformer. Nevertheless the relative energies and the barrier separating the conformers are not well established. By cryogenic trapping of a high temperature conformational mixture we investigated the conformational equilibrium of eight methyl substituted 1,3-butadienes. By varying the temperatures of the depositions and examining the resulting infrared spectra, vapor phase enthalpies of these equilibria were determined. The results obtained are in very good agreement with G3 ab-initio calculations and lead to insights into non-bonded interactions in conjugated dienes. The decay of the less stable conformers in neat samples trapped from high temperature depositions was monitored and showed matrix site effects in the solid state. These data were modeled by a gaussian distribution of activation energies and compared with G3 calculations of the activation energies. |
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Physical Organic, Materials, Heterocycles, Aromatics, Metal-Mediated Reactions
8:00 PM-10:00 PM, Tuesday, September 9, 2003 Hilton New York -- Americas Hall 1, Poster
Sci-Mix
Division of Organic Chemistry |