FT-IR Studies of N-(p-Cyanobenzylidene)-p-Octyloxyaniline, 4′-Cyanobenzylidene-4-n-Hexyloxyaniline and 4′-n- Hexyloxybenlidene-4-Cyanoaniline

Abstract

The phase transitions of three related liquid crystals, N-p-cyanobenzylidene)-p-octyloxyaniline (CBOOA), 4′-cyanobenzylidene-4-n-hexyloxyaniline (CBHA), and 4′-n-hexyloxybenlidene-4-cyanoaniline (HBAB) are studied by Fourier transform infrared spectrometry. The frequency, intensity and shape of the CN stretching band at 2200-2240 cm⁻¹ are examined as a function of temperature. Shifts in the frequency and changes in the integrated band intensity are correlated with the different mesogenic states. Although a shift in frequency is noted only at the crystal to first mesogenic transition, distinct changes in the integrated band intensity are present at each of the phase transitions.

Key Words:

• n-(p-cyanobenzylidene)-p-octyloxyaniline
• 4′-cyanobenzylidene-4-n-hexyloxyaniline
• hexyloxybenlidene-4-cyanoaniline
• FT-IR Band Shapes
• liquid crystal transitions