CONFORMATIONAL STUDIES OF 2-FLUOROETHANOL IN LIQUID XENON FROM TEMPERATURE-DEPENDENCE FT-IR SPECTRA

A variable temperature ( -45 degrees C to -100 degrees C) study of the infrared spectra (4000-400 cm(-1)) of 2-fluoroethanol, FCH2CH2OH, dis solved in liquid xenon has been performed. Some frequency shifts for a few fundamentals of the Gg' conformer (G indicates gauche conformatio n with respect to the C-C bond and g' to the C-O bond) between the gas phase values and those obtained from the xenon solution have been obs erved. The far infrared spectrum from 360 to 80 cm(-1) has been obtain ed for gaseous FCH2CH2OD. From these data the OD torsional fundamental is assigned at 238.5 cm(-1) for the Gg' conformer which indicates tha t the 345 cm(-1) band rather than the 308 cm(-1) band is the OH torsio nal fundamental for the FCH2CH2OH molecule. Gas phase infrared spectru m from 4000 to 400 cm(-1) at a resolution of 0.1 cm(-1) has been obtai ned for 2-fluoroethanol. The contours are compared to those predicted for the various conformers. The fundamental vibrational frequencies, h armonic force fields, infrared intensities, Raman activities (RHF/6-31 G), structural parameters and conformational stabilities have been ob tained from ab initio calculations at the MP2/6-31G* level and struct ural parameters and conformational stabilities have been obtained from MP2/6-311++G* calculations. The results are compared to those for th e other haloethanols. (C) 1998 Elsevier Science B.V. All rights reserv ed.