Mesomorphic study and DFT simulation of calamitic Schiff base liquid crystals with electronically different terminal groups and their binary mixtures

Ahmed, Hoda A.; Mansour, Eman A.; Hagar, Mohamed

doi:10.1080/02678292.2020.1794067

Cited by 28 publications

(16 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most reports have been focused on Schiff bases since the discovery of nematogenic 4-methoxybenzylidene-4′- butylaniline at room temperature [ 37 ]. Recently, several thermotropic Schiff base liquid crystals based on two rings were documented [ 32 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, liquid crystal (LC) materials have exhibited excellent applications in nonlinear optics [1], photonic devices [2], liquid crystal displays [3,4], and photo-switching materials [5]. The steric packing of rod-like geometry plays an important role in the phase transition phenomena of LC materials [6,7]. Symmetric and non-symmetric families of different linkages have been widely employed in the preparation of numerous LC materials [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Most reports are focused on Schiff bases since the discovery of nematogenic 4-methoxybenzylidene-4′-butylaniline at room temperature [ 18 ]. Recently, several thermotropic Schiff base/ester liquid crystals have been documented [ 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Mesomorphic study and DFT simulation of calamitic Schiff base liquid crystals with electronically different terminal groups and their binary mixtures

Cited by 28 publications

References 50 publications

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

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

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

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

Contact Info

Product

Resources

About