The assignment of the vibrational spectra of phenol has been reexamined on the basis of Raman and new IR measurements and theoretical analysis of the normal modes of vibrations in the electronic ground state. The infrared spectra of C 6 H 5 OH, C 6 D 5 OD, and C 6 D 5 OH have been studied in solution and vapor phases, as well as has the Raman spectra in solutions. New experimental data were obtained from infrared linear dichroism (IR-LD) studies of phenol aligned in uniaxially oriented nematic liquid crystal solution. The measured dichroic ratios and orientation factors indicate an effective C s symmetry of the molecule with coplanar orientation of OH bond with the benzene ring and supply unique information on the extent of symmetry lowering of benzene normal modes. The fundamental vibrational frequencies, force constants, and dipole derivatives have been calculated by ab initio quantum chemical methods applying the B3P86 density functional approximation with 6-311G** basis set. The force field optimized by means of a least-squares scaling procedure for phenold 0 (using six scale factors) was used to calculate the frequencies (with a mean deviation from the observed values less than 1%), normal modes, potential energy distributions, transition moment vectors, and IR intensities for phenol-d 0 , -d 1 , -d 5 , and -d 6 isotopomers. Compared to the deviations between the calculated and observed absorption intensities, a more satisfactory correlation was found between the calculated and experimentally determined Vibrational transition moment directions. The results indicate unanimously that the perturbation of the normal modes of benzene by the asymmetric hydroxyl substituent is so great that the previous practice of assigning the normal vibrations of phenol to those of benzene or even to C 2V symmetry species is not justified.

No abstract

An efficient synthetic method has been developed for the preparation of a new family of atropisomeric amino alcohols with 1-phenylpyrrole backbone. The synthesis is based on the different reactivities of the two carboxylic groups in optically active 1-[2-carboxy-6-(trifluoromethyl)phenyl]-1H-pyrrole-2-carboxylic acid (1). The chemical structures of the key intermediates were confirmed by spectroscopic methods and single crystal X-ray diffraction measurements. The very first application of a new optically active amino alcohol as catalyst for the enantioselective addition of diethylzinc to benzaldehyde demonstrated the practical usefulness of atropisomeric compounds in which there are six-atom chains between the two functional groups.

No abstract