scholarly journals Synthesis, Optical, and Geometrical Approaches of New Natural Fatty Acids’ Esters/Schiff Base Liquid Crystals

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4293 ◽  
Author(s):  
Alnoman ◽  
Al-Nazawi ◽  
Ahmed ◽  
Hagar
Keyword(s):  
Fatty Acids ◽  
Schiff Base ◽  
Liquid Crystals ◽  
Density Functional ◽  
Optical Transition ◽  
Molecular Structures ◽  
Frontier Molecular Orbital ◽  
Computational Calculations ◽  
Base Liquid ◽  
Methyl Phenyl

Schiff base liquid crystals, known as [4-(hexyloxy)phenylimino)methyl]phenyl palmitate (IA), [4-(hexyloxy)phenylimino)methyl]phenyl oleate (IIA) and [4-(hexyloxy)phenylimino)methyl]phenyl linoleate (IIIA), were synthesized from palmitic, oleic, and linoleic natural fatty acids. The prepared compounds have been investigated for their thermal and optical behavior as well as phase formation using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Molecular structures of all studied compounds were confirmed via elemental analysis, FT-IR, 1H NMR, and 13C NMR. Smectic phase is the observed mesophase for all compounds; however, their type and range depend upon the terminal alkanoate chains attached to the phenyl ring. Computational calculations, Density functional theory (DFT), energy difference of the frontier molecular orbital (FMOs), as well as the thermodynamic parameters of different molecular configurations isomers were discussed. It was found that the mesophase behavior and the geometrical characteristics were affected by the degree of unsaturation of fatty terminal chains. Furthermore, the geometrical structure of the CH=N linkage plays an important role in the thermal stability and optical transition temperature.

scholarly journals Polar Alkoxy Group and Pyridyl Effects on the Mesomorphic Behavior of New Non-Symmetrical Schiff Base Liquid Crystals

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1832
Author(s):  
Sayed Z. Mohammady ◽  
Daifallah M. Aldhayan ◽  
Mohammed A. Alshammri ◽  
Ayoub K. Alshammari ◽  
Mohammed Alazmi ◽  
...  
Keyword(s):  
Schiff Base ◽  
Liquid Crystals ◽  
Chain Length ◽  
Density Functional ◽  
Theoretical Calculations ◽  
13C Nmr Spectroscopy ◽  
Alkoxy Group ◽  
Thermal Stabilities ◽  
New Compounds ◽  
Base Liquid

A series of non-symmetrical Schiff base liquid crystals were prepared and investigated. Schiff bases of p-alkyloxy aniline derivatives and 4-phenyl pyridine-4′-carbaldehyde were synthesized. The terminal alkoxy groups substituting aniline are of varied chain length, namely C6, C8, and C16. The structures of the compounds were confirmed via 1H NMR and 13C NMR spectroscopy. Different mesophases of the samples were thermally and optically characterized by differential thermal analysis (DSC) and polarized optical microscopy (POM). All samples revealed enantiotropic smectic B (SmB) and smectic A (SmA) mesophases. The results obtained were further correlated with the density functional theory (DFT) theoretical calculations. The results are compared to a series of compounds bearing biphenyl moiety in their mesogens. The thermal stabilities of the different mesophase reduced upon the increment of the alkoxy chain length. The temperature ranges of both the smectic mesophases of new compounds bearing the 4-phenyl pyridine moiety are generally expanded higher than the other series. In addition, the total mesophase range is greater in the new compounds when compared to their biphenyl analogues. The DFT results were investigated in terms of the molecular geometries and the frontier molecular orbitals as well as the charge distribution mapping to show and illustrate the difference in the mesomorphic properties.

New two rings Schiff base liquid crystals; ball mill synthesis, mesomorphic, Hammett and DFT studies

2020 ◽  
Vol 299 ◽  
pp. 112161 ◽  
Author(s):  
Sherif S. Nafee ◽  
Mohamed Hagar ◽  
Hoda A. Ahmed ◽  
O.A. Alhaddad ◽  
Reda M. El-Shishtawy ◽  
...  
Keyword(s):  
Schiff Base ◽  
Liquid Crystals ◽  
Ball Mill ◽  
Dft Studies ◽  
Base Liquid

scholarly journals New wide-stability four-ring azo/ester/Schiff base liquid crystals: synthesis, mesomorphic, photophysical, and DFT approaches

RSC Advances ◽  
2020 ◽  
Vol 10 (16) ◽  
pp. 9643-9656 ◽  
Author(s):  
Nagwa H. S. Ahmed ◽  
Gamal R. Saad ◽  
Hoda. A. Ahmed ◽  
Mohamed Hagar
Keyword(s):  
Schiff Base ◽  
Liquid Crystals ◽  
Base Liquid ◽  
Dsc Thermograms

DSC thermograms of some prepared compounds: (a) recorded from second heating and (b) from cooling at a rate of ±10 °C min−1.

Influence of meta-extended rigid-core, complementary hydrogen bonding and flexible chain on polymorphism in Schiff-base liquid crystals: (4)MeOBD(3)AmBA:nOBAs

2019 ◽  
Vol 47 (4) ◽  
pp. 582-603
Author(s):  
AVSN Krishna Murthy ◽  
M. Srinivasulu ◽  
AVN Ashok Kumar ◽  
YV Rao ◽  
DM Potukuchi
Keyword(s):  
Hydrogen Bonding ◽  
Schiff Base ◽  
Liquid Crystals ◽  
Rigid Core ◽  
Flexible Chain ◽  
Base Liquid

SF5-Terminated Fluorinated Schiff Base Liquid Crystals

2004 ◽  
Vol 108 (52) ◽  
pp. 19940-19948 ◽  
Author(s):  
Jeremy A. Smith ◽  
Robert A. DiStasio ◽  
Nicole A. Hannah ◽  
Rolf W. Winter ◽  
Timothy J. R. Weakley ◽  
...  
Keyword(s):  
Schiff Base ◽  
Liquid Crystals ◽  
Base Liquid

scholarly journals Evaluation of α-Amylase Inhibitory Activity, Molecular Modeling, Total Antioxidant and Theoretical Studies of Novel Schiff Base Transition Metal Complexes

2020 ◽  
Vol 32 (9) ◽  
pp. 2187-2194
Author(s):  
A. SUDHA ◽  
S. ARULMOZHI ◽  
S.J. ASKAR ALI
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Schiff Base Ligand ◽  
Density Functional ◽  
Antioxidant Activities ◽  
Geometry Optimization ◽  
Docking Study ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Molecular Docking Study

By condensing pyrene-1-carbaldehyde and 4-aminoantipyrine, a Schiff base ligand, (Z)-1,5-dimethyl-2-phenyl-4-((pyren-1-ylmethylene)- amino)-1H-pyrazol-3(2H)-one and its Cu(II), Ni(II), Co(II) and Zn(II) complexes have been synthesized. The ligand and its metal complexes were characterized by FT-IR, UV-visible, 1H & 13C NMR, ESI-mass spectra and elemental analysis. The antidiabetic and antioxidant activities of the synthesized Schiff base ligand and its metal complexes were studied. The molecular docking study of human pancreatic α-amylase (PDB: 1HNY). Furthermore, Theoretical analysis of geometry optimization and frontier molecular orbital analysis (HOMOLUMO) was accomplished by density functional theory using B3LYP/3-21G*++ basis sets to understand the chemical stability of the synthesized ligand and their metal(II) complexes.

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