CHED 1376 |
| Experimental evidence suggests that ethers interact with singlet carbenes in solution to form ylides. In this project, the interaction between ethers and singlet carbenes was studied computationally in the gas phase and in solution. The singlet carbene investigated was methylene and the ethers investigated included dimethylether, diethylether, oxirane, methyloxirane, tetrahydrofuran, 1,4-dioxane, and 1,3,5-trioxane. The ylide complexes were characterized by calculation of optimized geometries, vibrational frequencies, and binding energies at the B3LYP and MP2 levels of theory using 6-31+G(d) and 6-311++G(d,p) basis sets. Solution phase binding energies and other properties for the carbene-ether complexes also were determined by the use of continuum solvation models. The amount of charge transfer from the ether to the carbene in the ylide was determined using Natural Population Analysis. In general, the ylide complexes exhibited stabilization in polar solvents relative to the gas phase, evidenced by a slight increase in binding energy, an increase in charge transfer, and a decrease in C-O distance. Correlations were observed between the charge transfer for the ylide and its relative basicity, as well as between other properties.
|
|
Undergraduate Research Poster Session: Physical Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |