Computational study of the keto/enol equilibrium in 2-fluoro-beta-diketones, (R1COCHFCOR2 with R2 = -CH3) and trifluormethyl-beta-diketones (R1COCH2COR2 with R2 = -CF3) using semiempirical method AM1

CHED 337

Juan G. Estevez, dawn@coqui.net1, Maria E. Maldonado1, Mariaury Perez1, and Lorna Ramirez-Velez, lornaramirezvele@hotmail.com2. (1) Department of Chemistry, University of Puerto Rico, # 205 Ave. Antonio R. Barcelo, Cayey, PR 00736, (2) University of Puerto Rico-Bayamon, Department of Chemistry, Bayamon, PR 00959
Given the growth of the number of compounds that contain fluorine, we have carried out calculations of 32 such compounds in their keto and enolic forms. We have calculated both R1COCHFCOR2 and R1COCH2COR2 with R1 = -CH3, ter-butyl-, -CF3, -Ph, 2-FPh-, 2-CH3Ph-, 2-CH3OPh-, 4-FPh-, 4-CH3Ph-, 4-NCPh-, 4-O2NPh-, 2-pyridyl, 2-pyrrolyl-, 2-furyl-, 2-thienyl-. For the calculations we have used semiempirical method AM1 using the optimization of energy provided in the computational package HyperChem. The results confirm the experimental data. The differences in the energies for the keto/enol equilibrium are between -2.006 Kcal/mol and + 0.593 Kacl/mol when R2= -CF3. . For the case with R2 = -CH3 the differences are: -1.610 Kcal/mol to 1.987 Kcal/mol. The equilibrium between enol a and enol b is discussed
 

Undergraduate Research Poster Session
2:30 PM-4:30 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Chemical Education

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007