Structural Studies of Semifluorinated n-Alkanes. 4. Synthesis and Characterization of F(CF₂)_nC₆H₄(CF₂)_nF by Conventional and Fourier Transform Raman Spectroscopy

A series of semiflexible fluorocarbon oligomers containing an aromatic core, F(CF2)nC8H4− (CF2)nF, have been synthesized and characterized by thermal analysis and both Fourier transform and conventional Raman spectroscopy. Measurements at ambient and low temperature and as a function of pressure were utilized to investigate the impact of the rigid ring on the low-frequency longitudinal acoustic mode (LAM) of the fluorocarbon chain. Normal-coordinate calculations as a function of chain length were performed to provide insight into molecular motion in the low-frequency region. © 1991, American Chemical Society. All rights reserved.