Investigations on smectic X* and re-entrant smectic C* orderings in hydrogen bonded ferroelectric liquid crystals

Kishor, Muchenedi Hari; Mohan, M. L. N. Madhu

doi:10.1016/j.molliq.2018.10.061

Cited by 15 publications

(3 citation statements)

References 34 publications

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“…Another report has studied the formation of angular complexes through intermolecular H-bond formation [16]. Several mesogenic derivatives containing the Schiff base as a central linking group have been reported [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Thermal and Mesomorphic Investigations of 1:1 Supramolecular Assemblies of 4-[(4-(n-Alkoxy)phenylimino)methyl]benzoic Acids Having Symmetrical and Un-Symmetrical Terminal Chain Lengths

et al. 2021

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Thermal and mesomorphic properties of possible 1:1 supramolecular complexes (SMCs) (Im/In) designed from two members of 4-[(4-(n-alkoxy)phenylimino)methyl]benzoic acid with symmetrical or un-symmetrical alkoxy terminal flexible chains (carbons of m and n = 6, 8 and 16), were analyzed by differential scan-calorimetry (DSC), thermogravemetric (TG) analysis, and their mesophases identified by polarized optical microscopy (POM). The equimolecular mixtures of the two acids possess symmetrical and un-symmetrical terminal lengths. The mesomorphic properties of the binary mixtures were examined as a function of the total alkoxy chain length on both sides. Results revealed that the nematic mesophase temperature range increases as the total terminal length increases for all designed un-symmetrical mixtures. A comparison was constructed between the formed SMCs and of those of the previously prepared 4-n-alkoxyphenylazo benzoic acids as well as the 4-n-alkoxy benzoic acids, to examine the impact of mesogenic core on the mesomorphic properties. The comparison indicated that as the mesogenic portion lengthens the thermal mesophase stability exhibits higher values of phase transition temperatures; whereas, the azo and Schiff base moieties exhibited near thermal properties.

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Section: Introductionmentioning

confidence: 99%

Thermal and Mesomorphic Investigations of 1:1 Supramolecular Assemblies of 4-[(4-(n-Alkoxy)phenylimino)methyl]benzoic Acids Having Symmetrical and Un-Symmetrical Terminal Chain Lengths

et al. 2021

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“…Another study looked at the production of angular complexes by the establishment of intermolecular H-bonds [21]. Several mesogenic derivatives, as a central linking group, have been reported in the formation of LC dimes [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

First Mesomorphic and DFT Characterizations for supramolecular assemblies of 3 (or 4)-n-alkanoyloxy benzoic acids and their optical applications

El‐Atawy

Khan

Popoola

et al. 2022

Preprint

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Successful preparation of new liquid crystalline 3 (or 4)-n-alkanoyloxy benzoic acids, were designed and fully characterized via experimental and theoretical approaches. Elucidation of their molecular structures were carried out by elemental analyses, NMR and FT-IR, spectroscopy. Thermal and mesomorphic properties of all symmetrical dimers having -symmetrical alkanoyloxy chain, were analyzed by differential scanning calorimetry (DSC) and their mesophases identified by polarized optical microscopy (POM). Results revealed that, the smectic mesophase covered all designed symmetrical dimers with thermal stability depending on the length of terminal alkanoyl moiety. Furthermore, the results of the Density Functional Theory (DFT) calculations supported the observed experimental data for the mesomorphic behaviour. The para-derivatives (In) of the alkanoyloxy benzoic acids were predicted to be stable with greater hydrogen bonding interactions than the meta (IIn) counterparts. The computed reactivity parameters revealed that the acids reactivity was influenced by the position of ester substituent. The absorbance spectra of both para and meso derivatives were noticed to be blue shifted with the increase of alky side, however, the energy band gap of meso-derivatives was found to be slightly higher than para-derivates. The synthesized materials exhibit broad photoluminescence spectrum which was noted to be red shifted with the increase of side chain length. The fluorescence lifetime was found to be increases with the increase of alkyl side chain length, and meso-derivatives have slightly longer lifetime as compared to the para-derivatives.

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“…Recently, density functional theory (DFT) becomes an essential routine method to correlate the outcome theoretical parameters with the experimental findings [38][39][40][41]. Several H-bonded mesogenic complexes containing azo, ester, and Schiff base central linkages have been widely reported [42][43][44][45][46][47]. Most of them are based on the linear intermolecular H-bonding interactions [48][49][50][51][52][53], and there are an attractive area of interest toward the formation of nonlinear SMHBLCs [54][55][56].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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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Investigations on smectic X* and re-entrant smectic C* orderings in hydrogen bonded ferroelectric liquid crystals

Cited by 15 publications

References 34 publications

Thermal and Mesomorphic Investigations of 1:1 Supramolecular Assemblies of 4-[(4-(n-Alkoxy)phenylimino)methyl]benzoic Acids Having Symmetrical and Un-Symmetrical Terminal Chain Lengths

Thermal and Mesomorphic Investigations of 1:1 Supramolecular Assemblies of 4-[(4-(n-Alkoxy)phenylimino)methyl]benzoic Acids Having Symmetrical and Un-Symmetrical Terminal Chain Lengths

First Mesomorphic and DFT Characterizations for supramolecular assemblies of 3 (or 4)-n-alkanoyloxy benzoic acids and their optical applications

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

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