Temperature-dependent Infrared Study of Phase Transitions in Bent-Core Liquid Crystalline Compound 12O(oh)2meo10

Temperature-dependent Fourier-transform infrared (FTIR) investigation on a novel four-ring bent-core liquid crystal ((4'-n-decyloxyphenylazo)-pheny1-4-y1-3-[N-(4'-n-dodecyloxy-2-hydroxybenzylidene) amino] -2-methyl benzoate) has been done to study the dynamics of the molecules in mesophases at the molecular level. The spectroscopic analysis revealed that specific modes gave a clear evidence of Cr reversible arrow SmC and SmC reversible arrow Ncybc phase transitions and successfully depicts the mechanism at these transitions. One of the important objectives to find the spectroscopic signature of the coexistence of SmC and cybotactic nematic N-cybc phases below N-cybc -> SmC phase transition up to 3 degrees C could not be achieved. FTIR spectroscopy confirmed the phase reversibility. In order to get the theoretical support density functional theory (DFT) has been adopted for conformational analysis that predicted the most stable conformer I. Conformer I might be expected closer to the real system and utilized for vibrational assignment along with potential energy distribution (PED). It has been demonstrated that the combination of FTIR spectroscopy and DFT paved a way to understand a candid picture of structural modification and dynamics of mesophases at the macromolecular level during the phase transitions. (C) 2017 Elsevier B.V. All rights reserved.