Vibrational spectroscopic study of 2-fluorophenol and 2,3,5,6-tetrafluorohydroquinone

The vibrational properties of two fluorophenol derivatives, 2-fluorophenol (1) and 2,3,5,6-tetrafluorohydroquinone (2), have been studied by FT-IR and FT-Raman spectroscopy. The spectra revealed the existence of two conformers for both compounds. A quantum chemical study of the title compounds was carried out at the B3LYP/6-311++G∗∗ level of theory. The computed harmonic force fields were scaled utilizing previously developed scale factors resulting in good agreement with experiment and facilitating the assignment of the vibrational spectra and a distinction between the two conformers. The wavenumbers of identified OH torsional modes support a stronger intramolecular O-H⋯F hydrogen bonding in 1 than in 2.