title: Vibrational assignment and structure of trifluorobenzoylacetone. A density functional theoretical study.
abstract: Molecular structure and vibrational frequencies of 4,4,4-trifluoro-1-phenyl-1,3-butanedione, known as trifluorobenzoylacetone (TFBA), have been investigated by means of density functional theory (DFT) calculations. The results were compared with those of benzoylacetone (BA), acetylacetone (AA), and trifluoroacetylacetone (TFAA). Comparing the calculated and experimental band frequencies and intensities suggests coexisting of both stable cis-enol conformers in comparable proportions in the sample. The energy difference between the two stable chelated enol forms is negligible, 0.96 kcal/mol, calculated at B3LYP/6-311++G** level of theory. The molecular stability and the hydrogen bond strength were investigated by applying the natural bond orbital (NBO) theory and geometry calculations. The theoretical calculations and spectroscopic results indicate that the hydrogen bond strength of TFBA is between those of TFAA and AA, considerably weaker than that of BA.
authors.affiliation: Department of Chemistry, University of Ferdowsi, Mashhad 91775-1436, Iran. Tayyari@ferdowsi.um.ac.ir
authors.forename: Sayyed Faramarz
authors.initials: SF
authors.lastname: Tayyari
authors.forename: Mohammad
authors.initials: M
authors.lastname: Vakili
authors.forename: Abdo-Reza
authors.initials: AR
authors.lastname: Nekoei
authors.forename: Hedayat
authors.initials: H
authors.lastname: Rahemi
authors.forename: Yan Alexander
authors.initials: YA
authors.lastname: Wang
mesh_terms: D002074:Butanones / Q000737:chemistry*; D004583:Electrons; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D010422:Pentanones / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D014732:Vibration
chemical_list: D002074:Butanones; D006845:Hydrocarbons, Fluorinated; D010422:Pentanones; C519063:trifluorobenzoylacetone; C008790:acetylacetone; C035851:benzoylacetone