Synthesis And Characterization Of Disubstituted Conjugated Ethynylated-Imine Derivatives As Potential Liquid Crystalline Materials

Abstract

A typical liquid crystalline material usually consists of rigid center, linker/bridge and flexible chain tail. By taking this in consideration, 15 novel compounds bearing ethynyl (C=C), imine (C=N) and alkoxy chain were introduced through condensation process of primary amines and aldehydes. This highly conjugated molecules with general formula of Donor-Ar(C=N)Ar(C=C)Ar(C=N)Ar-Donor are believed to exhibit liquid crystalline nature. All synthesized compounds were characterized spectroscopically and analytically via CHN Elemental Microanalysis, Fourier Transform Infrared (FTIR), Ultraviolet-Visible spectroscopy (UV-Vis), 'H and 'C Nuclear Magnetic Resonance (NMR), Thermogravimetric analysis (TGA). Scanning Electron Microscopy (SEM) and Cyclic voltammetry (CV) analysis. For liquid crystal study, Differential Scanning Calorimetry (DSC) and Polarized Optical Microscopy (POM) were carried out to give better understanding. The infrared spectra revealed the most significant bands of interest C=N and C=C at 161 7-1621 em'and 2201 -- 2209 cm' respectively which then were confirmed by the presence of C=N resonance around 8.31 -- 8.39 ppm and c 159.00 - 161.75 ppm in 'H and C NMR spectroscopies respectively.