scholarly journals Synthesis, Mesomorphic and Computational Characterizations of Nematogenic Schiff Base Derivatives in Pure and Mixed State

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2038
Author(s):  
Laila A. Al-Mutabagani ◽  
Latifah A. Alshabanah ◽  
Hoda A. Ahmed ◽  
Hafsa H. Alalawy ◽  
Mayada H. Al alwani
Keyword(s):  
Density Functional ◽  
Molecular Structures ◽  
Geometrical Parameters ◽  
Molecular Architecture ◽  
Aromatic Rings ◽  
Scanning Calorimetry ◽  
Binary Phase ◽  
Schiff Base Derivatives ◽  
Elemental Analyses ◽  
Ft Ir

Homolog series based on three aromatic rings bearing terminal alkoxy chain of various lengths named 4-(4-(alkoxy)phenylimino)methyl)phenyl nicotinate (An) were synthesized. The alkoxy-chain length changed between 6, 8 and 16 carbons. Mesomorphic and optical properties were carried out via differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Elemental analyses, FT-IR and NMR spectroscopy were carried out to elucidate the molecular structures of the prepared derivatives. Mesomorphic results indicated that all the synthesized homologs (An) are monomorphic possessing the nematic (N) phase enantiotropically with wide thermal stability. Computational simulations were measured via density functional theory (DFT) theoretical calculation tool. The estimated thermal and geometrical parameters are in agreement with the experimental data. By discussing the estimated parameters, it was found that the molecular architecture, dipole moment and the polarizability of the investigated compounds are highly affected by the length of the attached terminal flexible chain and the location of the nitrogen atom in the other terminal aromatic ring. Binary phase diagrams of two corresponding homologs with different proportionating terminals were constructed, and their binary phase physical properties were discussed in terms of the temperature range and stability of the N phase.

scholarly journals Synthetic, Mesomorphic, and DFT Investigations of New Nematogenic Polar Naphthyl Benzoate Ester Derivatives

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2587
Author(s):  
Salma A. Al-Zahrani ◽  
Hoda A. Ahmed ◽  
Mohamed A. El-atawy ◽  
Khulood A. Abu Al-Ola ◽  
Alaa Z. Omar
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Molecular Structures ◽  
Experimental Investigations ◽  
Geometrical Parameters ◽  
Polar Group ◽  
Scanning Calorimetry ◽  
Structural Shape ◽  
Elemental Analyses ◽  
Ft Ir

Four new non-symmetrical derivatives based on central naphthalene moiety, 4-((4–(alkoxy)phenyl) diazenyl)naphthalen–1–yl 4–substitutedbenzoate (In/x), were prepared, and their properties were investigated experimentally and theoretically. The synthesized materials bear two wing groups: an alkoxy chain of differing proportionate length (n = 6 and 16 carbons) and one terminal attached to a polar group, X. Their molecular structures were elucidated via elemental analyses and FT-IR and NMR spectroscopy. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) were carried out to evaluate their mesomorphic properties. The results of the experimental investigations revealed that all the synthesized analogues possess only an enantiotropic nematic (N) mesophase with a high thermal stability and broad range. Density functional theory (DFT) calculations were in accordance with the experimental investigations and revealed that all prepared materials are to be linear and planar. Moreover, the rigidity of the molecule increased when an extra fused ring was inserted into the center of the structural shape, so its thermal and geometrical parameters were affected. Energy gap predictions confirmed that the I16/c derivative is more reactive than other compounds.

scholarly journals New Nitro-Laterally Substituted Azomethine Derivatives; Synthesis, Mesomorphic and Computational Characterizations

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1927
Author(s):  
Mohamed A. El-atawy ◽  
Magdi M. Naoum ◽  
Salma A. Al-Zahrani ◽  
Hoda A. Ahmed
Keyword(s):  
Experimental Data ◽  
Molecular Geometry ◽  
Alkoxy Group ◽  
Molecular Structures ◽  
The Other ◽  
Molecular Architecture ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
Ft Ir ◽  
Chain Lengths

Two new homologues series, based on two rings of the azomethine central group bearing the terminal alkoxy group of various chain lengths, were prepared. The alkoxy chain length varied between 6 and 16 carbons. The other terminal wing in the first series was the F atom, and the compound is named N-4-florobenzylidene-4-(alkoxy)benzenamine (In). The second group of compounds included a lateral NO2 substituent in addition to the terminal F atom, named N-(4-fluoro-3-nitrobenzylidene)-4-(alkyloxy)aniline (IIn). Mesomorphic and optical properties were carried out via differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Elemental analyses, FT-IR, and NMR spectroscopy were carried out to elucidate the molecular structures of the synthesized groups. Mesomorphic investigations indicated that all the synthesized homologues (In) were monomorphic, possessing the smectic A (SmA) phase monotropically, while the second group (IIn) members were non-mesomorphic. The experimental data indicated that the formation of the mesophase is affected by the protrusion of the lateral nitro group. The disruption of the mesophase in the second group was attributed to the increase of its molecular width, which affects its lateral intermolecular interactions. The computational simulations were in agreement with the experimental data. On the other hand, the location of NO2 group within the molecular geometry increased the melting temperature of the molecule, and thus, affected their thermal and physical properties. By discussing the estimated parameters, it was found that the molecular architecture, the dipole moment, and the polarizability of the investigated compounds are highly affected by the electronic nature and position of the terminal and lateral substituents as well as their volumes.

scholarly journals Effect of the Relative Positions of Di-Laterally Substituted Schiff Base Derivatives: Phase Transition and Computational Investigations

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 870
Author(s):  
Fowzia S. Alamro ◽  
Hoda A. Ahmed ◽  
Saheed A. Popoola ◽  
Hamud A. Altaleb ◽  
Khulood A. Abu Al-Ola ◽  
...  
Keyword(s):  
Molecular Structures ◽  
Experimental Measurements ◽  
Positional Isomers ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Schiff Base Derivatives ◽  
Elemental Analyses ◽  
Ft Ir ◽  
Mesomorphic Properties ◽  
Ft Ir Spectroscopy

Two new laterally di-substituted derivatives namely, (E)-4-(((2-Chlorophenyl)imino)methyl)-3-methoxyphenyl 4-(alkoxy)benzoate, were designed and investigated for their mesomorphic properties. Elucidation of their molecular structures was carried out by elemental analyses, NMR and FT-IR, spectroscopy. Phase transitions were examined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The optimized geometrical architectures of both compounds were deduced theoretically using GAUSSIAN 09 program. In order to establish the most probable conformation for each compound, four probable conformations were predicted for their positional isomers which vary according to the orientations of the two lateral groups. The results were used to correlate the experimental measurements with the predicted conformations. The study revealed that the investigated derivatives are non-mesomorphic and the orientations, as well as positions of the two-lateral groups, have a significant effect on the molecular packing of the molecules, their geometrical and thermal parameters.

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

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4546
Author(s):  
Fowzia S. Alamro ◽  
Hoda A. Ahmed ◽  
Mohamed A. El-Atawy ◽  
Salma A. Al-Zahrani ◽  
Alaa Z. Omar
Keyword(s):  
Theoretical Data ◽  
Molecular Structures ◽  
Scanning Calorimetry ◽  
Polar Groups ◽  
Ir And Nmr Spectroscopy ◽  
Terminal Substituent ◽  
Computational Calculations ◽  
Elemental Analyses ◽  
Ft Ir ◽  
Polar Substituents

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.

Combined experimental and theoretical studies on molecular structures, spectroscopy of 4-(3-(2-amino-3,5-dibromophenyl)-1-(benzoyl)-4,5-dihydro-1H-pyrazol-5-yl)benzonitriles through NBO, FT-IR, HOMO-LUMO and NLO analyzes

2017 ◽  
Vol 16 (07) ◽  
pp. 1750057 ◽  
Author(s):  
R. Bharathi ◽  
N. Santhi
Keyword(s):  
Density Functional ◽  
Molecular Structures ◽  
Molecular Architecture ◽  
Functional Theory ◽  
Natural Bonding Orbital ◽  
Ft Ir ◽  
Experimental Values ◽  
Experimental And Theoretical Studies ◽  
Homo Lumo ◽  
Orbital Analysis

The pyrazole compounds 4-(3-(2-amino-3,5-dibromophenyl)-1-(4-substitutedbenzoyl)-4,5-dihydro-1H-pyrazol-5-yl) benzonitriles (4–6) have been synthesized and characterized by elemental, IR, 1HNMR spectral methods. In addition, the synthesized compounds were subjected to density functional theory for further understanding of the molecular architecture and optoelectronic properties. The optimized geometric parameters were in support of the corresponding experimental values. The FT-IR spectra of 4–6 have been investigated extensively using DFT employing B3LYP/6-31G (d,p) level theory. The molecular electrostatic potential analysis has been utilized to identify reactive sites of title compounds. Natural bonding orbital analysis proved the inter- and intra-molecular delocalization and acceptor–donor interactions based on the second-order perturbation interactions. The calculated band gap energies revealed that charge transfer occurs within the molecule. The polarizability and hyperpolarizability were calculated which show that compounds posses nonlinear optical nature.

scholarly journals New Symmetrical U- and Wavy-Shaped Supramolecular H-Bonded Systems; Geometrical and Mesomorphic Approaches

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1420 ◽  
Author(s):  
Laila A. Al-Mutabagani ◽  
Latifah Abdullah Alshabanah ◽  
Hoda A. Ahmed ◽  
Mohamed Hagar ◽  
Khulood A. Abu Al-Ola
Keyword(s):  
Density Functional ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Geometrical Structures ◽  
Functional Theory ◽  
Smectic C ◽  
The Density Functional Theory ◽  
Phenyl Rings ◽  
Ft Ir ◽  
Bonded Complexes

New mesomorphic symmetrical 2:1 supramolecular H-bonded complexes of seven phenyl rings were prepared between 4-n-alkoxyphenylazobenzoic acids and 4-(2-(pyridin-3-yl)diazenyl)phenyl nicotinate. Mesomorphic studies of the prepared complexes were investigated using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fermi bands of the formed H-bonded interactions were confirmed by FT-IR spectroscopy. Geometrical parameters for all complexes were performed using the density functional theory (DFT) calculations method. Theoretical results revealed that the prepared H-bonded complexes are in non-linear geometry with U-shaped and wavy-shaped geometrical structures; however, the greater linearity of the wavy-shaped compounds could be the reason for their stability with respect to the U-shaped conformer. Moreover, the stable, wavy shape of supramolecular H-bonded complexes (SMHBCs) has been used to illustrate mesomeric behavior in terms of the molecular interaction. The experimental mesomorphic investigations revealed that all complexes possess enantiotropic smectic C phase. Phases were confirmed by miscibility with a standard smectic C (SmC) compound. A comparison was constructed to investigate the effect of incorporating azophenyl moiety into the mesomeric behavior of the corresponding five-membered complexes. It was found that the addition of the extra phenylazo group to the acid moiety has a great increment of the mesophase stability (TC) values with respect to the monotropic SmC phase of the five aromatic systems to the high stable enantiotropic SmC mesophase.

scholarly journals Binary Liquid Crystal Mixtures Based on Schiff Base Derivatives with Oriented Lateral Substituents

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 319 ◽  
Author(s):  
Rua B. Alnoman ◽  
Mohamed Hagar ◽  
Hoda A. Ahmed ◽  
Magdi M. Naoum ◽  
Hanefah A. Sobaih ◽  
...  
Keyword(s):  
Schiff Base ◽  
Binary Mixtures ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Functional Theory ◽  
Schiff Base Derivatives ◽  
Lateral Group ◽  
Molecular Stacking

Binary mixtures of the laterally substituted Schiff base/ester derivatives, namely 4-((2- or 3-) substituted phenyl imino methyl) phenyl-4”-alkoxy benzoates, Ia–d, were prepared and mesomorphically studied by differential scanning calorimetry (DSC) and their mesophases identified by polarized optical microscopy (POM). The lateral group (1-naphthyl, 2-F, 2-Br, 3-F in Ia–d, respectively) is attached to different positions of the phenyl Schiff moiety. The mixtures investigated were made from two differently shaped compounds that differ from each other in the polarity, size, orientation, and relative positions of the lateral group. The results revealed that the binary mixture Ia/Ib (bearing the naphthyl and 2-flouro substituents) exhibited the SmA phase, which covered the whole composition range. For the mixtures Ib/Id (2-F and 2-Br), the isomeric lateral F-group in compound Ib distributed the SmA arrangement of Id. In the Ic/Id mixture bearing two positionally and structurally different substituents, the addition of Ic to Id resulted in solid binary mixtures where its behavior may be attributed to the negligible steric effect of the small electronegative fluorine atom compared to the Br atom. Density functional theory (DFT) theoretical calculations were carried out to estimate the geometrical parameters of individual components and to show the effect of these parameters in the mesophase behavior of the binary system, where the higher dipole moment of Id (6 Debye) may be the reason for its high π–π molecular stacking, which influences its mesophase range and stability.

scholarly journals Induced Phases of New H-bonded Supramolecular Liquid Crystal Complexes; Mesomorphic and Geometrical Estimation

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1549 ◽  
Author(s):  
Rua B. Alnoman ◽  
Hoda A. Ahmed ◽  
Mohamed Hagar ◽  
Khulood A. Abu Al-Ola ◽  
Bedor Sh. Alrefay ◽  
...  
Keyword(s):  
Density Functional ◽  
Aromatic Rings ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Smectic C ◽  
Computational Calculations ◽  
Theoretical Predictions ◽  
Temperature Ranges ◽  
Homo And Lumo ◽  
Ft Ir

New five rings architecture of 1:1 supramolecular hydrogen bonded (H-bonded) complexes were formed between 4-(2-(pyridin-4-yl)diazenyl-3-methylphenyl 4-alkoxybenzoates and 4-n-alkoxyphenyliminobenzoic acids. Mesomorphic and optical behaviors of three systems designed complexes were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). H-bonded interactions were confirmed via FT-IR spectroscopy. Computational calculations were carried out by density functional theory (DFT) estimation for all formed complexes. Experimental evaluations were correlated with the theoretical predictions and results revealed that, all prepared complexes possessing enantiotropic tri-mesophases with induced smectic C (SmC) and nematic temperature ranges. Moreover, DFT predicted for all formed supramolecular complexes possessing a non-linear bent geometry. Moreover, the π–π stacking of the aromatic rings plays an important role in the mesomorphic properties and thermal stabilities of observed phases. The energy changes between frontier molecular orbitals (HOMO and LUMO) and the molecular electrostatic potential (MEP) of the designed complexes were discussed and related to the experimental results.

scholarly journals New nematogenic conical-shaped supramolecular H-bonded complexes for solar energy investigations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sobhi M. Gomha ◽  
Hoda A. Ahmed ◽  
Mohamed Shaban ◽  
Tariq Z. Abolibda ◽  
Khalid Abdulaziz Alharbi ◽  
...  
Keyword(s):  
Solar Energy ◽  
Density Functional ◽  
Geometrical Structure ◽  
Energy Gap ◽  
Supramolecular Complexes ◽  
Geometrical Parameters ◽  
Scanning Calorimetry ◽  
Functional Theory ◽  
Ft Ir ◽  
Flexible Core

AbstractNew conical-shaped geometrical supramolecular H-bonded liquid crystal complexes were formed through 1:2 intermolecular interactions of H-bonding between flexible core (adipic acid, A) and lateral chloro-substituted azopyridines (Bn). The chains of the terminally alkoxy substituted base (n) were changed between 8 and 16 carbons. Mesomorphic and optical examinations of the prepared complexes were measured via differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fourier-transform infrared spectroscopy (FT-IR) was used to confirm the Fermi bands of the H- bonding interactions. Induced nematogenic mesophases that cover the whole lengths of alkoxy-chains were detected. The non-linear geometries of the designed supramolecular complexes were also confirmed via Density functional theory (DFT) calculations. It was found that the length of terminal alkoxy chain of the base moiety highly affects the geometrical structure of the investigated complexes. Moreover, it increases the thermodynamic energy and influences the geometrical parameters. The electrical properties of each of the acid component (A), the base (B16) and their 1:2 complex (A/2B16) were evaluated using the Keithley measurement-source unit. The optical properties studies showed that the influences in the optical absorption and the reduction of the energy gap of the complex compared to its individual components made the resulted supramolecular H-bonded complex soft material suitable for solar energy investigations.

A Density Functional Theory Study of 3,5-dichlorosalicyliden-p-iminoacetophenone oxime Complexes with Co, Ni, Cu and Zn Metals

2019 ◽  
Vol 41 (5) ◽  
pp. 770-770
Author(s):  
Ali apan Ali apan ◽  
Erdal Canpolat Erdal Canpolat ◽  
Henar Sleman and Niyazi Bulut Henar Sleman and Niyazi Bulut
Keyword(s):  
Metal Complexes ◽  
Density Functional ◽  
Azomethine Nitrogen ◽  
Carboxyl Oxygen Atom ◽  
Tetrahedral Geometry ◽  
Functional Theory ◽  
X Ray ◽  
Mechanical Methods ◽  
Elemental Analyses ◽  
Ft Ir

In this work, new Schiff baz ligand was synthesized by reaction of p-iminoacetophenone oxime with 3,5-dichlorosalicylaldehyde. Metal complexes of Co+2, Ni+2, Cu+2 and Zn+2 acetate metal salts were synthesized with this ligand. The ligand and complexes are characterized in experimental by their elemental analyses, X-ray, 1H-NMR, 13C-NMR, UV-Vis, FT-IR, magnetic susceptibility and thermogravimetric analyses (TGA) and also have been investigated by using quantum mechanical methods. The transition metals are coordinated to the schiff base through the azomethine nitrogen and the carboxyl oxygen atom. Obtained metal complexes were studied the magnetic properties and their geometries were determined. Co+2, Ni+2 and Zn+2 complexes have been found tetrahedral geometry and Cu+2 complex has been found four coordinated geometry.

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