Experimental and Theoretical Investigations of Three-Ring Ester/Azomethine Materials

Abstract

New three-ring ester/azomethine homologues series, (E)-4-((4-hydroxybenzylidene)amino)phenyl 4-(alkoxy)benzoate In, were prepared and their properties were investigated experimentally and theoretically. FT-IR, NMR, and elemental analyses were used to confirm the chemical structures of the synthesized compounds. The mesomorphic activities of the planned homologues were evaluated using differential scanning calorimetry (DSC) and polarized optical microscopy. All of the homologous examined were found to have non-mesomorphic properties. Theoretical calculations using the density functional theory (DFT) were used to validate the experimental data and determine the most stable conformation of the synthesized compounds. All calculated conformers’ thermal properties, dipole moments, and polarizability were discussed. The results show that the terminal alkoxy chain length affects the thermal parameters of the conformers. The correlations between these parameters’ values and the conformer type were demonstrated. The base component was expected to be in two conformers according to the orientation of the N atom of imine-linkage. DFT calculations revealed the more probable of the two possible conformers, and the incorporation of the alkoxy terminal chain in one position affect its geometrical and mesomerphic characteristics.

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

“…Moreover, the magnitude of the computed isotropic polarizability was found to be size dependent with the I12 having the largest value while the I6 has the least. Regarding the Frontier molecular orbitals (FMO’s) portrayed in Figure 4 , the similar molecular distribution recorded for the corresponding HOMO and LUMO of all the derivatives could be attributed to the closeness in their respective HOMO and LUMO energy levels [ 57 , 58 ]. In the case of the HOMO, the electron clouds were steadily distributed over the nitrogen and oxygen atoms of imidazolone unit, nitrogen and carbon atoms together with π bond of the -HN-N=CH-linkage.…”

“…Similar chemical reactivity was predicted for all the compounds ( In ) studied, as the values of parameters computed for each of the corresponding reactivity parameters were almost the same. This observation suggests that the reactivity of the derivatives is less sensitive to the size of the system [ 58 ]. On the part of the dipole moment highlighted in Table 2 , the higher value calculated for I10 over others is an indication of greater polarity.…”

“…In addition, an appreciable electron density distribution was observed over some carbon atoms and π-electrons of the phenoxide. The high electron deficiency predicted for the terminal alkyl group could be associated with the consequential effect of the –O-C=O linkage that resonantly stabilizes the phenoxide ring via electron withdrawal [ 58 ]. On the part of the LUMO, the even spreading of electron clouds occurred over the nitrogen and oxygen atoms of imidazolone together with the sigma bond between the OC-N section of imidazole ring.…”

Design of Liquid Crystal Materials Based on Palmitate, Oleate, and Linoleate Derivatives for Optoelectronic Applications

“…Numerous rod-like LC materials have been generated from Schiff bases and extensively examined [ 26 , 27 , 28 , 29 , 30 , 31 ]. Different impacts, including the orientation of the ester group within the rigid core, the position of the Schiff base unit with regard to the ester group, the lateral substitution [ 32 ], and the length of the terminal chain [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], have been studied.…”

Wide Nematogenic Azomethine/Ester Liquid Crystals Based on New Biphenyl Derivatives: Mesomorphic and Computational Studies

“…A twist-bend nematic phase has been observed in several Schiff bases, low-molecularmass liquid crystals [17][18][19][20]. Recent studies have been conducted on syntheses and research activities in this area [8,[21][22][23][24][25]. On the other hand, a wide range of terminal substituents, such as small polar compact substituents and alkoxy chains, are employed [26][27][28][29][30].…”