@article{paperid:202490, author = {منصوره زاهدی and Farba Tayyari and Zainab Moosavi-Tekyeh and Alireza Jalali and Tayyari, Sayyed Faramarz}, title = {Structure and vibrational assignment of the enol form of 1,1,1-trifluoro-2,4-pentanedione}, journal = {Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy}, year = {2006}, volume = {65}, month = {March}, issn = {1386-1425}, pages = {387--396}, numpages = {9}, keywords = {Vibrational spectra; Trifluoro-acetylacetone; Density functional theory; Intramolecular hydrogen bond; anharmonicity 1. Introduction It is well known that the cis-enol form of -diketones is characterized by a strong intramolecular hydrogen bond [1–4]. The simplest members of this class of compounds are malonaldehyde (MA) and acetylacetone (AA); which have been the subject of many theoretical and experimental studies [5–15]. IR; Raman; NMR;X-ray; neutron; and electron diffraction studies onAAand its derivatives [16–28] indicate that substitution of the methyl groups of AA has a drastic effect on both the position of ketoenol equilibrium and the strength of the intramolecular hydrogen bond. It is well known that the electron-withdrawing substitutes; such as fluorine atom; increase the enol content of -diketones [26–30]. By means of vibrational spectroscopy [4;17;19;20]; ∗ Corresponding}, }