Induced Nematic Phase of New Synthesized Laterally Fluorinated Azo/Ester Derivatives

Abstract

A new series of laterally fluorinated mesomorphic compounds, namely 2-fluoro-4-((4-(alkyloxy)phenyl)diazenyl)phenyl 4-substitutedbenzoate (Inx) were prepared and evaluated for their mesophase behavior. The synthesized series constitutes five members that possess different terminally attached polar groups (X). Their molecular structures were confirmed by elemental analyses and both FT-IR and NMR spectroscopy. Examination of the prepared derivatives was conducted via experimental and theoretical tools. Mesomorphic investigations were carried by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). DSC and POM measurements indicated that except for the un-substituted analogue, all other derivatives were purely nematogenic, possessing their nematic (N) mesophase enantiotropically. This is to say that insertions of terminal polar substituents on their mesogenic structures induced the N phase. In addition, the location of lateral and terminal polar moieties played a considerable role in achieving good thermal N stability. Computational calculations were investigated to determine the deduced optimized molecular structures. Theoretical data indicated that both size and polarity of the terminal substituent (X) have essential impact on the thermal parameters and optical properties of possible geometries.

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System

“…It could be concluded that the kind and the thermal stability of the formed phases facilitate the molecular space-filling due to the attached terminals that influence the physical geometrical parameters to enhance the intermolecular attractions between molecules. Moreover, the high electron density predicted for the carbonyl oxygen of -OCO-linkage together with the appreciable quantity recorded for that of -C=N-linkage, as reflected in Figure 5, suggests significant contribution of these linkages to the derivatives' polarizability, which is an important factor that increases the mesophase thermal stability of a compound [56,57].…”

“…Figure 5, suggests significant contribution of these linkages to the derivatives' polarizability, which is an important factor that increases the mesophase thermal stability of a compound [56,57].…”

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].…”

New Self-Organizing Optical Materials and Induced Polymorphic Phases of Their Mixtures Targeted for Energy Investigations

“…The position and spatial orientation of fluorine atom further influence properties of nematogenic materials. The physical characteristics of the resulting liquid crystalline material, such as melting and phase transition temperatures, mesomorphic morphology, dipole moment, and dielectric anisotropy, were significantly influenced by the combination of the lateral fluorine atom’s small size and high polarity [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”