Vinyl‐terminated side‐chain liquid‐crystalline polyethers containing mesogenic benzylideneaniline moieties

Abstract

The synthesis of two vinyl‐terminated side‐chain liquid‐crystalline polyethers containing benzylideneaniline moieties as mesogenic cores was approached in two different ways: by chemically modifying poly(epichlorohydrin) with suitable mesogenic acids or by polymerizing analogous glycidyl ester or glycidyl ether derivatives. In all the conditions tested, the first approach led to materials in which the imine group was hydrolyzed. The second approach led to the desired polymers PG2a and PG2b, but only from the glycidyl ether derivatives and when the initiator was the system that combined polyiminophosphazene base t‐Bu‐P4 and 3,5‐di‐t‐butylphenol. These polymers were chemically characterized by IR and 1H and 13C NMR spectroscopies. The estimated degrees of polymerization ranged from 30 to 36. The liquid crystalline behavior of the synthesized polymers was studied by differential scanning calorimetry, polarized optical microscopy (POM) and X‐ray diffraction. Both polymers behave like liquid crystals and exhibited a single mesophase, which was recognized as a smectic C mesophase, probably with a bilayer arrangement, i.e., a smectic C2 mesophase. The crosslinking of both polymers was performed with dicumyl peroxide as initiator, which led to liquid crystalline thermosets. POM and X‐ray diffraction confirmed that the mesophase organization mantained on the crosslinked materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1877–1889, 2006

An attempt of molecular design and synthesis of 3,4′/4,3′-disubstituted benzylideneanilines with specified UV-Vis absorption maximum wavelength

“…Some organic compounds containing classical π conjugate system are applied well in many fields of optical function materials due to their potential optoelectronic properties . The benzylideneanilines are a kind of typical compounds that have π conjugate system; their polymers and coordination compounds are important optical functional compounds and have been applied extensively in the fields of liquid crystal and NLO material . For example, Ramamurthi et al have made many linear and nonlinear studies deeply about the compounds of 4‐bromo‐4′‐chloro benzylideneaniline and 4‐bromo‐4′‐dimethylamino benzylideneaniline, and attained meaningful results.…”

“…[4][5][6][7] The benzylideneanilines are a kind of typical compounds that have π conjugate system; their polymers and coordination compounds are important optical functional compounds and have been applied extensively in the fields of liquid crystal and NLO material. [3,[8][9][10] For example, Ramamurthi [11,12] et al have made many linear and nonlinear studies deeply about the compounds of 4-bromo-4′-chloro benzylideneaniline and 4-bromo-4′-dimethylamino benzylideneaniline, and attained meaningful results. The previous studies of benzylideneanilines mostly focus on the synthesis, photoelectric performance and quantitative molecular structure-performance relationship.…”

Substituent effects on the 13C NMR chemical shifts of the imine carbon in N‐(4‐X–benzylidene)‐4‐(4‐Y–styryl) anilines

“…[1][2][3] It has been reported that when the electron density of the carbon nucleus increases, the field of resonance also increases. [4,5] Substituent effects on 13 C NMR have been investigated. [6][7][8] Several 13 C NMR studies have revealed that the overall electron distribution can be finely tuned through the electronic effects of remote substituents.…”

“…[4,5] Substituent effects on 13 C NMR have been investigated. [6][7][8] Several 13 C NMR studies have revealed that the overall electron distribution can be finely tuned through the electronic effects of remote substituents. [9][10][11] Substituted benzylidene anilines are widely used structural units in liquid crystals and nonlinear optical materials.…”

“…[9][10][11] Substituted benzylidene anilines are widely used structural units in liquid crystals and nonlinear optical materials. [12][13][14][15] Neuvonen and co-workers [16] demonstrated that changes of the substituents X and Y could finely control the electronic character, and the presence of the specific cross-interaction between X and Y in M3 (Scheme 1) was verified. Cao et al [17] further explored the substituent-specific cross-interaction effects in the same system and successfully proposed the new parameter Δs 2 (Δs 2 = (s X À s Y ) 2 ) to scale the effects, where the s X and s Y are Hammett constants of the substituents X and Y, respectively.…”