RAMAN-SPECTROSCOPIC STUDY OF THE LOW-FREQUENCY VIBRATIONS IN ANISOLE-D5 AND ANISOLE-D8

Low-frequency Raman spectra of solid anisole-d5 and anisole-d8 have been measured at 130 K. The phenyl-d5 torsion, which is observed at 140 cm-1 in the spectrum of anisole-d5, is shifted to lower frequency and hidden under lattice bands in the case of anisole-d8. The twofold barrier calculated from the observed torsional frequency is 3892 ± 85 cm-1. The methyl torsional mode was observed at 280 cm-1 in the spectrum of solid anisole-d5 and at 177 cm-1 in the spectrum of solid anisole-d8. The threefold barriers calculated from these frequencies are 1820 ± 20 cm-1 and 1422 ± 18 cm-1, respectively. The barrier values indicate that the methyl torsion is coupled to the low-frequency ring torsion mode (δ CC). © 1979.