Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Ahmed, Hoda A.; Khushaim, Muna

doi:10.3390/cryst10100878

Cited by 12 publications

(7 citation statements)

References 51 publications

(69 reference statements)

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“…It was found that the insertion of a lateral group on the aromatic ring of the mesogenic part influenced the mesophasic transition temperature range of the smectic phases [ 22 , 23 , 24 ] and increased spontaneous polarization [ 25 ]. The existence of mesophases near room temperature is very important for potential applications; consequently, lateral moieties are incorporated into the molecular architecture to lower the melting temperature [ 26 ]. On the other hand, polar terminal substituents and linking moieties were both important factors for the designed compounds, in terms of the formation, kind, thermal stability, and range of the observed mesophase [ 5 , 12 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…On the other hand, the kind of the symmetrical and unsymmetrical terminal substituents will affect the mesomorphic phenomena [30][31][32][33]. Thus, when a change of the length of the terminal alkyl/alkoxy chains is affected and the rigidity of the structural molecular core is altered, the linearity of the molecules will be accordingly changed, to some extent, due to the higher number of the chain configurations that lead to different interactions between linear molecules [34,35].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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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“…The small volume of the lateral group enables its additions into the mesomorphic architectures without being sterically disrupted, and consequently, its LC mesophases can still be observed. It has also been documented that lateral or terminal polar substituent induces an effect on the mesomeric properties of huge numbers of Schiff bases/ester derivatives [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Optical Characterizations and Solar Energy Applications of New Schiff Base Materials

et al. 2021

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A new set of laterally OCH3-substituted photoactive liquid crystalline analogues, 4-hexyloxy phenyl- imino-4ʹ-(3-methoxyphenyl)-4ʹ’-alkoxybenzoates, were synthesized and investigated for their mesomorphic behavior. The prepared set constitutes five analogues that differ from each other by the terminally attached compact polar group. Characterization of the synthesized derivatives is conducted using differential scanning calorimetry (DSC), polarized optical microscopy (POM), and UV-spectroscopy. Molecular structures were elucidated by elemental analyses, FT-IR and NMR spectroscopy. DSC and POM investigations indicated that all the prepared derivatives are monomorphic possessing the nematic (N) phase, except for the unsubstituted derivative that is nonmesomorphic. On the other side, the photophysical study and the optical spectra measurements confirm the photoactivity of the present compounds under UV/visible irradiation. The measured optical spectra showed impressive enhancement in the optical absorption and reduction in the optical bandgap from 3.63 to 3.0 eV depending on the terminal group. From the study of the DC electric properties, the lowest resistance, 106.5 GΩ at scan rate 0.1 V/s, was observed for the I6d film with Cl terminal, which decreased to 49.5 GΩ by increasing the scan rate to 0.5 V/s. Moreover, the electrical conductance is decreased from 9.39 pS to 1.35 pS at scan rate 0.1 V/s by changing the terminal group from Cl to F. The enhanced optical absorption and the reduced energy gap make the optimized samples suitable material for solar energy applications.

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Nematogenic Laterally Substituted Supramolecular H-Bonded Complexes Based on Flexible Core

Cited by 12 publications

References 51 publications

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

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

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

Synthesis, Optical Characterizations and Solar Energy Applications of New Schiff Base Materials

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