Synthesis and Mesomorphic Properties of New Fluorinated Schiff Base Liquid Crystals

Ha, Sie‐Tiong; Lee, Teck-Leong

doi:10.1155/2014/904657

Cited by 13 publications

(5 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Saccone et al suggested that on changing the degree of fluorination, the fine tuning of temperature is possible over a mesomorphic range [23]. Phillips and Pombeiro, and others have reported that the addition of halogen atom in a drug molecule may increase its liophilicity and also the addition of halogen atom induces strong dipole moment within the liquid crystal and these results in the enhancement of lattice stability [24][25][26][27]. This also increases the ionic radius of the molecule and makes it more parallel in the alignment within an electrode [28].…”

Section: Introductionmentioning

confidence: 99%

A theoretical investigation of nonlinear optical and electronic molecular parameters of hexabutyloxytryphenylene and halogenated hexabutyloxytryphenylene molecules using density functional theory (DFT) for nonlinear device applications

Pal¹,

Mishra²,

Singh³

et al. 2022

Phys. Scr.

View full text Add to dashboard Cite

In this work, we discuss the molecular properties of hexabutyloxytryphenylene (HAT4) and halogenated HAT4 using density functional theory (DFT) with B3LYP method and Pople basis set (6-31G, 6-31G*, 6-31G**) for the generation of non-linear optical and electronic parameters. Using DFT method, the dependence of electro-optical parameters of halogenated HAT4 such as dipole moment, mean polarizability, anisotropy in polarizability and hyperpolarizability along with global parameters such as ionization potential, electron affinity, electronegativity, chemical hardness and electrophilicity index on the halogens in the core of the considered molecules has been studied in this work. Further, the frontier molecular orbital analysis for pure HAT4 and halogenated HAT4 molecules has been carried out. The proposed study helps us to analyse the effect of halogenation on the linear, non-linear as well as thermodynanical properties of HAT4 molecules such as HOMO-LUMO gap, thermal energy, entropy and specific heat capacity. The effect of halogenation also leads to understand the modification of nonlinear parameters of HAT4 for the interaction of nonlinear fields.

show abstract

Section: Introductionmentioning

confidence: 99%

A theoretical investigation of nonlinear optical and electronic molecular parameters of hexabutyloxytryphenylene and halogenated hexabutyloxytryphenylene molecules using density functional theory (DFT) for nonlinear device applications

Pal¹,

Mishra²,

Singh³

et al. 2022

Phys. Scr.

View full text Add to dashboard Cite

show abstract

“…It was reported in [13] that the dipole moment of the mesomeric portion of the molecule impacts the type and stability of the mesophase produced, which is dependent on the attached terminal polar substituent and the steric one that varies according to size. The halogen substituent at the terminal position showed strong influence on the mesomorphic behavior of the Schiff base molecules [30]. In our present study, the halogenated compound C (X = I) is dimorphic, with the highest thermal nematic stability (182.0 °C) and SmA stability (136.3 °C).…”

Section: Resultsmentioning

confidence: 53%

The Synthesis of New Thermal Stable Schiff Base/Ester Liquid Crystals: A Computational, Mesomorphic, and Optical Study

et al. 2019

View full text Add to dashboard Cite

A Schiff base supramolecular 4-[(4-(hexyloxy)phenylimino)methyl]benzoic acid and a new series of Schiff base/ester linkages named 4-substitutedphenyl 4-[(4-(hexyloxy)phenylimino)methyl]benzoate liquid crystals were synthesized. The thermal stability, mesomorphic, and optical behavior of the prepared compounds were characterized by differential scanning calorimetry (DSC), Thermogravemetric analysis (TGA), polarized optical microscopy (POM), and UV spectroscopy. FT-IR, 1H-NMR, 13C-NMR, and elemental analyses were carried out to elucidate and confirm the molecular structures of the synthesized compounds. The investigated series comprising different sized terminal polar groups changed between CH(CH3)2, H, I, and F. It was found that the supramolecular imino acid dimer is enantiotropic dimorphic, with a wide SmA phase and a good N phase range. The other series of terminally substituted Schiff base/esters are mesomorphic with a high thermal stable SmA phase, except the iodo derivative, which showed dimorphic SmA and N phases. The effect of the position and the orientation of the cores, as well as the terminal substituent of the type and the stability of the mesophase, were studied. A computational theoretical study of the effects of the van der Waal’s volume, the Hammett substituent coefficient, the inductive sigma constant, and other geometrical parameters were discussed. The study revealed that the planarity of the two phenyl rings attached with an imino linking group impacted the resonance effect of the terminal substituents rather than their inductive effect. A detailed study on the effect of the estimated thermal parameters, as well as their geometrical planarity with the type and stability of the formed mesophase, was discussed.

show abstract

“…Halogen (F, Cl, Br) groups at the terminal position showed strong impact on the mesomorphic properties of a molecule. The melting and transitions temperatures of current compound, 8BrBA are higher than those of 8FBA [39] and 8ClBA [40]. The size of bromine atom is larger in comparison with fluorine and chlorine atoms and the electrons on the bromine atom are loosely held and far from the nucleus.…”

Section: Methodsmentioning

confidence: 81%

“…Molecular structure of organic compounds and their liquid crystalline properties are closely correlated. Table 2 lists the transition temperatures and mesomorphic behaviors of 8BrBA and structurally related compounds [25,[39][40][41].…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Mesogenic Properties of New Aromatic Schiff Base’s Esters

Lee,

Chelsea,

et al. 2023

AChJ

View full text Add to dashboard Cite

A homologous series of new Schiff base’s esters, 4-bromobenzylidene-4’-alkanoyloxyanilines were syn-thesized. The structure of the synthesized compounds was elucidated using IR and NMR spectroscopic techniques along with mass spectrometric method. Nine homologous members were prepared whereby the length of alkanoyloxy chain, Cn-1H2n-1COO is varied from n = 2, 4, 6, 8, 10, 12, 14, 16 and 18. Their thermotropic properties were analyzed using differential scanning calorimetry and polarized optical mi-croscopy techniques. Whilst short chain members (number of carbons, n = 2, 4) are non-mesogens, member with n = 6 exhibited monotropic smectic A (SmA) phase. As the n increased to 8, this com-pound becomes the only member that exhibited SmA and SmB as enantiotropic phase. Varying from n = 10 to n = 16, these members displayed enantiotropic SmA and monotropic SmB phases. Longest chain member, n-octadecanoyloxy derivatives exhibited only single mesophase (monotropic SmA). The ester linkage and polar terminal (bromo) group in the present series are essential for the smectic polymorphism in Schiff bases

show abstract

Synthesis and Mesomorphic Properties of New Fluorinated Schiff Base Liquid Crystals

Cited by 13 publications

References 31 publications

A theoretical investigation of nonlinear optical and electronic molecular parameters of hexabutyloxytryphenylene and halogenated hexabutyloxytryphenylene molecules using density functional theory (DFT) for nonlinear device applications

A theoretical investigation of nonlinear optical and electronic molecular parameters of hexabutyloxytryphenylene and halogenated hexabutyloxytryphenylene molecules using density functional theory (DFT) for nonlinear device applications

The Synthesis of New Thermal Stable Schiff Base/Ester Liquid Crystals: A Computational, Mesomorphic, and Optical Study

Synthesis and Mesogenic Properties of New Aromatic Schiff Base’s Esters

Contact Info

Product

Resources

About