BARRIER TO ROTATION OF CH3, CF3, and CCl3 GROUPS IN ACETONE AND ITS HALO DERIVATIVES

The structure of acetone has been studied by microwave spectroscopy [1-3]. According tothese studies, the barrier to rotation for CH3 group is in the 265-274 cm-1 range [1]. Pace etal. [4] reassigned the vibrational spectra of hexafluoroacetone, HFA, by assuming a C2vstructure. These authors, based on the calorimetric measurements in the gas phase, predicteda barrier to rotation for the CF3 groups of about 4.2-6.3 kJ/mol (350-527 cm-1) [4]. No data isavailable about CCl3 rotation in hexachloroacetone, HCA. The aim of this study is calculatingof CH3, CF3, and CCl3 in acetone and its halo derivatives by DFT method.