Synthesis, Optical and DFT Characterizations of Laterally Fluorinated Phenyl Cinnamate Liquid Crystal Non-Symmetric System

A new laterally fluorinated unsymmetric liquid crystalline homologous series, based on cinnamate linkage, named 2-fluoro-4-(4-(alkoxy)phenyl)diazenyl)phenyl cinnamate (In), was synthesized and evaluated via different experimental and computational tools. The series had different terminal alkoxy-chain lengths with a lateral F atom in the meta position with respect to the azo moiety. The experimental mesomorphic and optical investigations were carried out using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Theoretical calculations and geometrical parameter predictions were conducted using the DFT program method at B3LYP/6-311G** level of theory. The results revealed that all the designed compounds exhibited the nematic (N) mesophase enantiotropically. The nematic stability and temperature range were impacted by the terminal alkoxy chain length. Compounds with the shortest chains (I6 and I8) showed a monotropic smectic A (SmA) phase, while the longest chain derivative, I16, possessed enantiotropic Sm A phase. Theoretical density functional theory (DFT) predictions were correlated with the practically observed data from the mesomorphic investigations. Data revealed that the terminal alkoxy and lateral F groups had an essential impact on the total energy of possible geometrical structures and their physical and thermal parameters.

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Chair- and V-Shaped of H-bonded Supramolecular Complexes of Azophenyl Nicotinate Derivatives; Mesomorphic and DFT Molecular Geometry Aspects

Molecules ◽

10.3390/molecules25071510 ◽

2020 ◽

Vol 25 (7) ◽

pp. 1510 ◽

Cited By ~ 3

Author(s):

Omaima A. Alhaddad ◽

Khulood A. Abu Al-Ola ◽

Mohamed Hagar ◽

Hoda A. Ahmed

Keyword(s):

Hydrogen Bonding ◽

Density Functional ◽

Liquid Crystalline ◽

Molecular Geometry ◽

Supramolecular Complexes ◽

Scanning Calorimetry ◽

Geometrical Structures ◽

Functional Theory ◽

Ft Ir ◽

Nematic Phases

New geometrical architectures of chair- and V-shaped supramolecular liquid crystalline complexes were molded through 1:1 intermolecular hydrogen bonding interactions between 4-(4-(hexyloxy)phenylazo)methyl)phenyl nicotinate and 4-alkoxybenzoic acids. The length of terminal alkoxy acid chains varied, n = 6 to 16 carbons. The mesomorphic behaviour of these complexes was examined through differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Fourier-transform infrared spectroscopy (FT-IR) was carried out to confirm the presence of Fermi bands that appeared for the hydrogen bonding formation. Enantiotropic nematic phases were observed and covered all lengths of alkoxy chains. The geometrical structures of the prepared supramolecular complexes geometries were estimated by Density functional theory (DFT) calculations. The supramolecular complexes I/An are projected to exhibit a nonlinear geometry with V-shaped and chair-shaped geometry. The chair-shaped conformers of I/An were found to be more stable than V-shaped isomeric complexes. Moreover, the effect of the change of the mesogenic core on the mesophase thermal stability (TC) has been investigated by a comparative study of the present azo supramolecular H-bonding LCs (SMHBCs) I/An and our previously reported their Schiff base analogue complexes, II/An. The findings of the DFT illustrated the high impact of CH=N as a mesogenic core on the mesomorphic behavior in terms of the competitive lateral and terminal intermolecular interactions as well as the molecular electrostatic potential (MEP).

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Pyridine-Based Three-Ring Bent-Shape Supramolecular Hydrogen Bond-Induced Liquid Crystalline Complexes: Preparation and Density Functional Theory Investigation

Crystals ◽

10.3390/cryst11060628 ◽

2021 ◽

Vol 11 (6) ◽

pp. 628

Author(s):

Sayed Z. Mohammady ◽

Daifallah M. Aldhayan ◽

Mohamed Hagar

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Liquid Crystalline ◽

Compact Groups ◽

Geometrical Structures ◽

Thermal Stabilities ◽

Functional Theory ◽

Aspect Ratios ◽

Enthalpy Changes ◽

Chain Lengths

A series of new supramolecular three-ring bent-shape Schiff base liquid crystal (LC) complexes were prepared and studied. On one side, two alkoxy chain lengths of the carboxylic acids were used, namely eight and sixteen carbons. Moreover, on the other side, terminal small compact groups, which substituted aniline, with different polarities were utilized. Furthermore, the hydrogen-bonding interactions in the formed complexes were elucidated by Fourier-transform infrared (FT–IR) spectroscopy. The mesomorphic thermal and optical characteristics of the samples were determined by differential thermal analysis (DSC) and polarized optical microscopy (POM). The complexes exhibited enantiotropic and dimorphic mesophase behaviors. The results indicate that the polarity of the compact groups and the lengths of the alkoxy chains greatly impacted the mesomorphic characteristics and thermal stabilities of the mesophases. The observed values of the enthalpy changes (ΔH) associated with the crystalline smectic-A (TCr-SmA) transitions were extremely small compared with the conventional values that characterize supramolecular hydrogen-bonded liquid crystalline complexes. ΔH, which corresponded to the nematic isotropic transitions (TN-I), varied from 0.13 to 9.54 kJ/mol depending mainly on the polarity of the groups that were para-attached to the aniline moiety. Finally, the theoretical results obtained by density functional theory (DFT) calculations were discussed. The DFT geometrical structures showed non-coplanar structures. The mesomorphic range was correlated with the calculated dipole moment, polarizability and the aspect ratios of the investigated compounds.

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Preparation and DFT Study for New Three-Ring Supramolecular H-Bonded Induced Liquid Crystal Complexes

Frontiers in Chemistry ◽

10.3389/fchem.2021.679528 ◽

2021 ◽

Vol 9 ◽

Author(s):

Sayed Z. Mohammady ◽

Daifallah M. Aldhayan ◽

Mohamed Hagar

Keyword(s):

Liquid Crystal ◽

Density Functional ◽

Theoretical Calculations ◽

Compact Groups ◽

Scanning Calorimetry ◽

Thermal Stabilities ◽

Functional Theory ◽

Enthalpy Changes ◽

Bonding Interaction ◽

Chain Lengths

Supramolecular three-ring Schiff base novel liquid crystal complexes have been prepared and investigated. Schiff bases of para-substituted aniline derivatives and para-pyridine carbaldehyde have been prepared and then mixed in equimolar quantities with para-alkoxy benzoic acids. On one side, the alkoxy chain length varies from 8 to 16 carbon atoms. On the other side, terminal small compact groups substituting aniline with various polarities are used. Hydrogen-bonding interaction was elucidated by FTIR spectroscopy. The mesomorphic thermal and optical characteristics of the samples were obtained by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). All samples exhibit enantiotropic mesophases. Experimental results obtained for the induced mesophases were correlated with density functional theory (DFT) theoretical calculations. The results revealed that both the polar compact groups’ polarity and the alkoxy chain lengths contribute strongly to mesomorphic characteristics and thermal stabilities of the mesophases. Surprisingly, the observed values of enthalpy changes associated with the crystalline mesomorphic transitions lie in the range of 2.2–12.5 kJ/mol. However, the enthalpy changes corresponding to the mesomorphic–isotropic transitions vary from 0.9 to 13.9 kJ/mol, depending on the polarity of para-attached groups to the aniline moiety.

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ADSORPTION REACTION OF POLAR ORGANIC MOLECULES ON ${\rm Si}^+_n$ CLUSTER IONS

International Journal of Modern Physics B ◽

10.1142/s0217979205031225 ◽

2005 ◽

Vol 19 (15n17) ◽

pp. 2502-2507

Author(s):

WAKANA NAKAGAWARA ◽

HIRONORI TSUNOYAMA ◽

ARI FURUYA ◽

FUMINORI MISAIZU ◽

KOICHI OHNO

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Organic Molecules ◽

Theoretical Calculations ◽

Cluster Ions ◽

Silicon Cluster ◽

Geometrical Structures ◽

Functional Theory ◽

Relationship Of ◽

The Relationship

We have examined chemical reactions of small silicon cluster ions [Formula: see text] for n = 7 - 16 with polar organic molecules M ( M = CH 3 CN , CD 3 OD , C 2 H 5 CN , and C 2 H 5 OH ). The intensities of the adsorption products [Formula: see text] for m = 1 and 2 were investigated as a function of n. We found for all polar molecules that the relative intensity of Si n M + to the unreacted [Formula: see text] is smaller for n = 11, 13, and 14, that is, the adsorption reactivity is smaller for these n than others. It was also commonly observed that the [Formula: see text] ion are more intense than neighboring n. We discussed the relationship of the reactivity with the geometrical structures and the stabilities of the bare [Formula: see text] ions and adsorbed [Formula: see text] ions, from theoretical calculations based on density functional theory.

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

Molecules ◽

10.3390/molecules25061420 ◽

2020 ◽

Vol 25 (6) ◽

pp. 1420 ◽

Cited By ~ 8

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.

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

Crystals ◽

10.3390/cryst10040319 ◽

2020 ◽

Vol 10 (4) ◽

pp. 319 ◽

Cited By ~ 3

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.

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Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

Materials ◽

10.3390/ma12142314 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2314 ◽

Cited By ~ 3

Author(s):

David Ester ◽

Declan McKearney ◽

Khrystyna Herasymchuk ◽

Vance Williams

Keyword(s):

Density Functional Theory ◽

Organic Semiconductors ◽

Self Assembly ◽

Density Functional ◽

Liquid Crystalline ◽

Variable Temperature ◽

Phase Behaviour ◽

Scanning Calorimetry ◽

Functional Theory ◽

Thiadiazole Ring

Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5”-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, thiadiazole derivatives formed smectic C and soft crystal lamellar phases, and maintained lamellar order down to room temperature. Variation of the terminal alkyl chains also influenced the observed phase sequence. Single crystal structures revealed the face-to-face orientation of molecules within the layers in the solid-state, a packing motif that is rationalized based on the shape and dipole of the thiadiazole ring, as corroborated by density functional theory (DFT) calculations. The solution opto-electronic properties of the systems were characterized by absorption and emission spectroscopy, cyclic voltammetry, and time-dependent density functional theory (TD-DFT).

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Optical and Geometrical Characterizations of Non-Linear Supramolecular Liquid Crystal Complexes

Crystals ◽

10.3390/cryst10080701 ◽

2020 ◽

Vol 10 (8) ◽

pp. 701 ◽

Cited By ~ 3

Author(s):

Hoda A. Ahmed ◽

Mohamed Hagar ◽

Omaima A. Alhaddad ◽

Ayman A. Zaki

Keyword(s):

Self Assembly ◽

Density Functional ◽

Liquid Crystalline ◽

Theoretical Calculations ◽

Scanning Calorimetry ◽

Crystalline Materials ◽

The Density Functional Theory ◽

Different Temperatures ◽

Ft Ir ◽

Liquid Crystalline Materials

Nonlinear architecture liquid crystalline materials of supramolecular 1:1 H-bonded complexes (I/II and I/III) were prepared through a self-assembly intermolecular interaction between azopyridine (I) and 4-n-alkoxybenzoic acid (II) as well as 4-n-alkoxyphenylazo benzoic acid (III). The H-bond formation of the prepared supramolecular hydrogen bonded (SMHB) complexes was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Optical and mesomorphic behaviors of the prepared complexes were studied by polarized optical microscopy (POM) as well as DSC. Theoretical calculations were performed by the density functional theory (DFT) and used to predict the molecular geometries of the synthesized complexes, and the results were used to explain the experimental mesomorphic and optical properties in terms of their estimated thermal parameters. Ordinary and extraordinary refractive indices as well as birefringence at different temperatures were investigated for each sample using an Abbe refractometer and modified spectrophotometer techniques. Microscopic and macroscopic order parameters were calculated for individual compounds and their supramolecular complexes.

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Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

10.26434/chemrxiv.7072577.v1 ◽

2018 ◽

Author(s):

Mihails Arhangelskis ◽

Athanassis Katsenis ◽

Novendra Novendra ◽

Zamirbek Akimbekov ◽

Dayaker Gandrath ◽

...

Keyword(s):

Density Functional Theory ◽

Mechanochemical Synthesis ◽

Thermodynamic Stability ◽

Experimental Evaluation ◽

Density Functional ◽

Theoretical Calculations ◽

Zeolitic Imidazolate Framework ◽

Functional Theory ◽

Calorimetric Measurements ◽

And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

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Optical investigations and photoactive solar energy applications of new synthesized Schiff base liquid crystal derivatives

Scientific Reports ◽

10.1038/s41598-021-94533-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Fowzia S. Alamro ◽

Sobhi M. Gomha ◽

Mohamed Shaban ◽

Abeer S. Altowyan ◽

Tariq Z. Abolibda ◽

...

Keyword(s):

Solar Energy ◽

Liquid Crystalline ◽

Molecular Structures ◽

Light Illumination ◽

Electrical Measurements ◽

Scanning Calorimetry ◽

Energy Applications ◽

Meta Position ◽

Chain Group ◽

Liquid Crystalline Materials

AbstractNew homologues series of liquid crystalline materials namely, (E)-3-methoxy-4-[(p-tolylimino)methyl]phenyl 4-alkloxybenzoates (I-n), were designed and evaluated for their mesomorphic and optical behavior. The prepared series constitutes three members that differ from each other by the terminally attached alkoxy chain group, these vary between 6 and 12 carbons. A laterally OCH3 group is incorporated into the central benzene ring in meta position with respect to the ester moiety. Mesomorphic characterizations of the prepared derivatives are conducted using differential scanning-calorimetry (DSC), polarized optical-microscopy (POM). Molecular structures were elucidated by elemental analyses and NMR spectroscopy. DSC and POM investigations revealed that all the synthesized derivatives are purely nematogenic exhibiting only nematic (N) mesophase, except for the longest chain derivative (I-12) that is dimorphic possesses smectic A and N phases. Moreover, all members of the group have a wide mesomorphic range with high thermal nematic stability. A comparative study was established between the present derivative (I-6) and their previously prepared isomer. The results indicated that the location exchange of the polar compact group (CH3) influences the N mesophase stability and range. The electrical measurements revealed that all synthesized series I-n show Ohmic behaviors with effective electric resistances in the GΩ range. Under white light illumination, the effective electric conductivity for the compound I-8 is five times that obtained in dark conditions. This derivative also showed two direct optical band gaps in the UV and visible light range. In addition, I-6 has band energy gaps of values 1.07 and 2.79 eV, which are suitable for solar energy applications.

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