24176-64-5Relevant academic research and scientific papers
MICROWAVE SPECTRA AND INTERNAL ROTATION OF 4-FLUOROPHENOL, 4-CHLOROPHENOL AND 4-BROMOPHENOL
Larsen, N. W.
, p. 83 - 100 (1986)
The microwave spectra of 4-fluorophenol, 4-chlorophenol and 4-bromophenol are analysed in the frequency region 18-40 GHz.The vibrational ground state with two torsional sublevels are assigned for the following molecular species: 4-F-C6H4OH(I), 4-F-C6H4OD(II), 4-(35)Cl-C6H4OH(III), 4-(37)Cl-C6H4OH(IV), 4-(35)Cl-C6H4OD(V), 4-(79)Br-C6H4OH(IV) and 4-(81)Br-C6H4OH(VII).The spectra consist of μa- and μb-lines.The μb-lines appear as doublets with approximately constant splittings of 354 MHz(I), 2.25 MHz(II), 159 MHz(III and IV), 0.75 MHz(V) and 139 MHz(VI and VII).The μa-lines are unsplit except for I in which a few μa-lines appear as closely spaced doublets.Coriolis type interaction between the torsional substates was observed for I and was proved to be responsible for the splitting of the μa-lines.Assuming a semirigid model the effective twofold barriers to internal rotation of the hydroxyl group are calculated to be 1006 cm-1(I), 1035 cm-1(II), 1148 cm-1(III and IV), 1179 cm-1(V) and 1172 cm-1(VI and VII).All the molecules are shown to be planar and structural information about the OH group has been obtained for I and III.
Structure of 4-fluorophenol and barrier to internal -OH rotation in the S1-state
Ratzer, Christian,Nispel, Michael,Schmitt, Michael
, p. 812 - 819 (2003)
The structure and barrier to internal rotation of 4-fluorophenol in the ground state and the electronically excited S1-state has been examined by resonantly enhanced two photon ionization spectroscopy and by rotationally resolved laser induced fluorescence spectroscopy of 4-fluorophenol and 4-fluorophenol-d1. The rotationally resolved spectrum of the electronic origin of 4-fluorophenol is comprised of two subbands, which are split by 174.1 ± 0.5 MHz. From the splitting, determined from the HRLIF and several torsional bands observed in the R2PI spectrum an excited state barrier for the internal rotation of the hydroxy group of 1819.0 ± 5 cm-1 was calculated. The subtorsional splitting of 4-fluorophenol-d1 could not be resolved. The experimentally determined structural parameters from a fit to the rotational constants and the barrier to internal rotation in both electronic states are compared to the results of ab initio calculations. The molecule shows quinoidal distortion upon electronic excitation, with a shortening of both the C-O and the C-F bonds.
