Synthesis and Study of Novel Liquid Crystalline Homologous Series: 4-(4′-n-Alkoxy Benzoyloxy)-3-Methoxy Phenyl azo-3″, 4″ Dichlorobenzenes

Chauhan, B. C.; Doshi, A. A.; Doshi, A. V.

doi:10.1080/15421406.2012.720856

Cited by 16 publications

(8 citation statements)

References 5 publications

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“…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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“…Relatively low melting behavior of a series and shorter mesophase length are attributed to the predominancy of the weaker intermolecular adhesion forces Downloaded by [University of Birmingham] at 18:38 22 March 2015 (i) operated by broadening of the molecules. The mesomorphic properties of a presently investigated series 1 are compared with other known structurally similar homologous series X [15] and Y [16] as shown in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Study of Mesomorphism Through a Novel Homologous Series and Its Relation to Molecular Structure

Doshi

Chauhan²

2015

Molecular Crystals and Liquid Crystals

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A novel homologous series 4-(4 -n-alkoxy benzoyloxy)-3-chloro phenyl azo,3 ,4 -dichlorobenzenes was synthesized with a view to understand and establish the relation between mesomorphism and the molecular structure. The novel series consists of 12 members, which showed commencement of monotropic nematic mesophase formation from the butoxy homologue and continued up to the hexadecyloxy homologue without exhibition of a smectic mesophase. The textures of the nematic mesophase are threaded or Schlieren in type. Transition temperatures were determined by an optical polarizing microscope equipped with a heating stage. Isotropic-nematic transition curve of the phase diagram behaved in normal manner with exhibition of odd-even effect. Solidisotropic transition curve behaved descending tendency by adopting zigzag path up to the pentyloxy homologue; which include methoxy to propoxy homologues as nonmesomorphic derivatives. Thermal stability for the nematic is just a few degrees (1 • C to 2 • C). Analytical and spectral data support the molecular structures. The mesomorphic properties of present novel series are compared with structurally similar other known homologous series.

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“…[13][14][15][16][17] Liquid crystal materials bearing azo/ester central linkages and middle and terminal phenyl rings substituted with groups of different polarity as well as nalkoxy group on the other end of the molecule were reported. [18][19][20][21][22][23][24][25][26][27] In previous work [28] in this laboratory, the effect of compact terminal substituent (X), as well as the terminal alkoxy (RO-) group, of varying chain length, on the mesophase behaviour of compounds of the type 4-(4′-substituted phenylazo) phenyl 4″-alkoxybenzoates (IIn af ) was studied. In that work, [28] it was observed that the stability of the mesophase is augmented by an increase in the polarity and/or polarisability of the mesogenic part of the molecule, which is definitely affected by the polarity of the substituent, and its position, which would accordingly affect the polarity of the whole molecular structure by the way the polar substituents electronically interact with the remainder of the molecule.…”

Section: Introductionmentioning

confidence: 99%

Effect of exchange of terminal substituents on the mesophase behaviour of some azo/ester compounds

et al. 2014

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Six homologous series of 4-(4′-alkoxy phenylazo) phenyl 4″-substituted benzoates (In a-f ) were prepared in which, within each homologous series, the length of the terminal alkoxy chain varies between 6, 8, 10, and 12 carbons, while the other terminal substituent, X, is a polar group that alternatively changed from CH 3 O, CH 3 , H, Br, NO 2 and CN. Compounds prepared were characterised by spectroscopic methods, and their mesophase behaviour investigated by differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The results were discussed in terms of mesomeric and polarisability effects. In each group of compounds, bearing the same alkoxy substituent, the nematic-to-isotropic transition temperatures (T C ) were successfully correlated with the polarisability anisotropy of bonds to the substituent X. A comparative study was made between the investigated compounds and their previously prepared isomers, namely, 4-(4′-substituted phenylazo) phenyl 4″-alkoxybenzoates (IIn a-f ) in which the two terminal (alkoxy-and X) groups are exchanged.

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Synthesis and Study of Novel Liquid Crystalline Homologous Series: 4-(4′-n-Alkoxy Benzoyloxy)-3-Methoxy Phenyl azo-3^″, 4^″ Dichlorobenzenes

Cited by 16 publications

References 5 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

Study of Mesomorphism Through a Novel Homologous Series and Its Relation to Molecular Structure

Effect of exchange of terminal substituents on the mesophase behaviour of some azo/ester compounds

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