Vibrational spectra of fluorinated aromatics. XIII. Benzotrifluoride

Abstract

The infrared absorption spectrum of gaseous benzotrifluoride has been obtained with a 1-m cell and a Perkin-Elmer double-pass spectrometer equipped with NaCl and CsBr prisms. The Raman spectrum of liquid C₆H₅CF₃ has been photographed with a 3-prism glass spectrograph of reciprocal linear dispersion 15 A/mm at 4358 A, and depolarization ratios have been measured for most of the Raman bands. Under the assumptions that the molecule has approximately the symmetry C_2v and that phenyl and CF₃ vibrations are weakly coupled, all but 3 of the vibrational fundamentals have been assigned and classified as follows: Species a₁: 336, 770, 1004, 1028, 1072, 1180, 1457, 1614, 2995, 3022, and 3096 cm⁻¹; Species b₁: 199, 618, 902, 1127, 1237, 1362, 1457, 1614, 3022, and 3096 cm⁻¹; Species b₂: 139, 485, 695, 770, (800), and 923 cm⁻¹; Species a₂: 235, 844, and (ca 950) cm⁻¹; CF3 vibrations: (ca 150), 321, 398, 596 (2 funds.), 657, 1152 (2 funds.), and 1328 cm⁻¹. The spectra have been interpreted in detail.