Synthesis, characterisation and liquid crystalline behaviour of some lanthanides complexes containing two azobenzene Schiff base

Azobenzene-Containing Schiff-Bases—Syntheses and Dyes Applications

“…And finally for nickel complexes, only a transition phase from crystal to isotropic was found upon heating [90]. [86]; of bis(azo) LC2 [62], of halogenated LC3 [88]; of series A and B LC4 [89]; LC5 series [90].…”

“…In this process, azobenzene Schiff-base ligands were synthesized that can form one-sided and two-sided Schiff bases by changing the amino and diamino. Khalil K. Abid et al [62] also synthesized azobenzene Schiff bases using pre-existing azo compounds. In that case, the diamines formed Schiff bases with aldehydes on both sides.…”

“…As a result, an azobenzene Schiff base with an amine (47) at the phenyl on the azo group side and an aldehyde bound from the outside was obtained. Khalil K. Abid et al [62] also synthesized azobenzene Schiff bases using pre-existing azo compounds. In that case, the diamines formed Schiff bases with aldehydes on both sides.…”

“…Upon heating and cooling, all the synthesized azo Schiff-based LC1 series (Figure 5) exhibited two phase transitions, from crystal to nematic and from nematic to isotropic while heating to 285 • C and reversely on cooling to 169 • C [86]. When two azobenzene Schiff base are linked by a propylenediamine moiety (LC2, Figure 5), and are complexing lanthanides, smectic A phases are observed while heating to 80 • C (Ligand alone), 90 • C (La(III) and Ce(III) complexes), 91 • C (Sm(III) complex) and 75 • C (Gd(III) complex) [62]. When cholesteryl mono-, bis-or tripodal molecules were performed with branched azobenzenes, it was shown that the liquid crystal phase behavior was closely related to the number of mesogenic units and the rigidity and flexibility of the structure.…”

Synthesis and characterization of fluorinated poly(azomethine ether)s from new core-fluorinated azomethine-containing monomers

“…[22] Additionally, the incorporation of the aliphatic moieties and flexible ether linkages into the polymer chains of PAMs (in particular, in PAMEs) is sufficient to induce LC properties to such macromolecular compounds. [3,6,23] On the other hand, it is known that introduction of fluorine atoms into polymers' structure enhances their thermal stability and chemical resistance, as well as allows reduction the polymers' dielectric constant, the refractive index, optical losses at the same time improving their ability to form LC eluent were used in this study. Differential scanning calorimetry (DSC) was performed by a TA Instruments Q-2000 apparatus (United States) at a heating rate of 20 K/min.…”