Naphthyl azomesogens with lateral chloro groups

Abstract

A homologous series of azomesogens, 2″-[4-(4′-n-alkoxybenzoyloxy)-2-chlorophenylazo] naphthalenes, with lateral chloro groups was synthesised. All the homologues synthesized exhibit enantiotropic nematic mesophase. The mesomorphic properties of the present series are compared with other structurally related series to evaluate the effect of lateral chloro group and its position on mesomorphism.

Mesogenic quinazolone derivatives: synthesis and characterisation

“…The smectic mesophase length and the thermal stabilities of compound 9 are lower by 13 C and 36 C, respectively, as compared with the structurally related compound A [22][23][24][25][26][27][28]. Also, the nematic Table 3.…”

“…Gray [33] has explained that increases in molecular breadth reduce both nematic and smectic mesophase thermal stability. This is also reflected in the comparison of compounds 21 and B [22][23][24][25][26][27][28]. Enantiotropic nematic behaviour was observed for compound B, whereas compound 21 has a monotropic nematic phase with both lower mesophase length and thermal stability by 5 C and 24 C, respectively, as compared with compound B, because the L/B ratio for compound 21 (L/B: 3.06) is lower as compared with compound B (L/B: 4.59).…”

“…The thermal stability and mesophase length as a measure of mesomorphism can be correlated with the molecular constitution of the compounds. Figure 3 summarises the molecular structure, transition temperatures and energy-minimised ball and stick model (MM2 models derived from CS Chemdraw Ultra 7.0 software) with length and breadth of the n-decyloxy derivative of the present series I and II (compounds 9 and 21) and structurally related compounds A and B reported in the literature [22][23][24][25][26][27][28]. Compound 9 exhibits enantiotropic SmA and nematic mesophases, while compound 21 exhibits only monotropic nematic mesophase.…”

“…on mesomorphism [22][23][24][25][26][27][28]. In this paper, we report the synthesis and characterisation of two homologous series of Schiff's base ester having quinazolone moiety, and compare their mesomorphic properties with each other and with the mesogenic homologous series containing the naphthalene moiety in the molecular core, in order to evaluate the effect of lateral methoxy substituent and quinazolone heterocyclic moiety on mesomorphism.…”

Synthesis and Characterization of Azo Compounds and Study of the Effect of Substituents on Their Liquid Crystalline Behavior

“…Mesogens with aromatic substituents have been prepared [2,3,4,5,6,7]. Recently a homologous series of mesogenic azo compounds containing three rings in the main core and substituted with aromatic or hydroxyl groups on the central benzene nucleus was reported [8,9]. The mesogenic homologous series with hydroxyl group substituents exhibited nematic mesomorphism, whereas the homologous series with aromatic branches exhibited smectogenic tendencies.…”