Synthesis and polarized light‐induced birefringence of new polymethacrylates containing carbazolyl and azobenzene pendant groups

Low T_g copolymers of [11(N‐carbazolyl)undecylmethacrylate] and [2,5‐dimethylphenyl‐[(4‐nitrophenyl)azo]‐phenoxyalkylmethacrylate] have been synthesized and the polarized light‐induced birefringence of thick films (70 μm) has been investigated at a constant deducted temperature relative to T_g (T − T_g = 10 °C). The optical properties of these copolymers have been studied in relation to the azo‐dye content and the length of the alkyl spacer between the azo‐dye and the methacrylic backbone. They have been compared with the dispersion of (4‐methoxy‐2,5‐dimethylphenyl)‐(4‐nitrophenyl)diazene (DMNPAA) within a poly[11(N‐carbazolyl)undecyl‐methacrylate] and a poly[N‐vinylcarbazole] (PVK) matrix. The experimental curves have been fitted by biexponentials, so emphasizing the effects of the copolymer structure on the kinetics of the writing process. The photoinduced orientation is more than three orders of magnitude higher in a grafted material compared to the dispersion version. The azo‐dye concentration also has an important role in both the amplitude and the dynamics of the photo‐orientation. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 205–213, 2000     

Adsorption of direct black-38 azo dye on p-tert-butylcalix[6]arene immobilized material

The present study demonstrates the adsorption of the direct black-38 (DB-38) azo dye on potential and newly synthesized p-tert-butylcalix[6]arene based silica resin (4). Resin 4 was synthesized via the modification of pure silica 1 as 2 followed by the immobilization of p-tert-butylcalix[6]arene (3) onto modified silica (2). It was characterized by using different analytical techniques such as FT-IR, scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). The effect of adsorbent dosage, pH and the electrolyte effect on the removal of the DB-38 azo dye were evaluated through batch wise adsorption experiments. Maximum adsorption of 91% was achieved at pH 9.0. The textile wastewater samples were used to ensure the field applicability of the newly synthesized adsorbent 4 for the treatment of dye contaminated effluents. All results regarding the removal of the DB-38 azo dye from the aqueous environment prop up resin 4 as an effective adsorbent and it was found that resin 4 has high adsorption efficiency toward the DB-38 azo dye at a wide range of pH as compared to 1 and 2.     

Synthesis and Phase Behavior of Azo Dye Containing Liquid Crystalline Polyorganosiloxane

Abstract

A series of liquid crystalline polyorganosiloxanes containing both azo dye and cholesteryl groups were synthesized by reacting poly[3- chloroformylpropyl)methylsiloxane-co-dimethylsiloxane] with both cholesterol and 4-(4′-methoxyphenylazo)phenol. The yields were between 73 and 81%. Most of these new polyorganosiloxanes are colored solid products. Their chemical structures were confirmed by IR, ¹H NMR, and elemental analysis. Their phase behaviors were also investigated by using differential scanning calorimetry (DSC) and polarizing microscopy. The results show that all these polyorganosiloxanes exhibit liquid crystalline behavior at various temperatures and at any azo dye content. As a result of the orientation of both mesogenic azo dye and cholesteryl groups, smectic phases were formed beginning around 0°C, and cholesteric phases appeared above 60°C.     

Synthesis and thermo-XRD-analysis of the organo-clay color pigment

An intense blue organo-clay color pigment was obtained by adding naphthyl-1-ammonium chloride to a Na-montmorillonite aqueous suspension followed by treatment with sodium nitrite. This treatment resulted in the synthesis of the azo dye 4-(1-naphthylazo)-1-naphthylamine adsorbed onto the clay. The pigment was subjected to thermo-XRD-analysis and the diffractograms were curve-fitted. Heating naphthylammonium-montmorillonite at 360°C resulted in the evolution of the amine at temperatures lower than those required for the formation of charcoal and consequently the clay collapsed. On the other hand, heating the pigment at 360°C resulted in the conversion of the adsorbed azo dye into charcoal. The clay did not collapse, thus proving that the azo dye was located inside the interlayer space. Before the thermal treatment a short basal spacing in the pigment compared with that in the ammonium clay (1.28 and 1.35 nm, respectively) indicated stronger surface π interactions between the clayey O-plane and the azo dye than between this plane and naphthylammonium cation. The amount of dye after one aging-day of the synthesis-suspension increased with [NaNO₂]/[C₁₀H₇NH₃] ratio but did not increase with naphthylammonium when the [NaNO₂]/[C₁₀H₇NH₃] ratio remained 1. After 7 and 56 aging days it decreased, indicating that some of the dye decomposed during aging.     

“推拉”型Schiff碱染料LB膜二阶非线性光学性质的研究

具有非线性光学性质（NLO）的“推拉”型结构分子由于在光学通讯、电光器件和激光扫描等光电子领域中具有潜在的应用价值,近十几年已被广泛研究。这类分子的典型结构为D－π-A（D为电子给体,A为电子受体,π为共轭体系）,容易发生分子内的电荷转移而具有大的分子超极化率,有机分子的结构与二阶非线性光学性质（SHG）的相关性在理论和实验方面已有研究,但不同取代位置的电子受体对SHG垢影响的报道则较少。     

Design of Organoiron Macromolecules Based on Upper Rim Functionalized Calix[4]arenes

The versatility of cationic cyclopentadienyliron complexes is demonstrated for the generation of calix[4]arene‐based dendrimers and polymers. Dendrimers were prepared from a branched organoiron calix[4]arene through subsequent reactions of azo dyes and organoiron complexes. The resulting azo dye‐containing metallocalix[4]arenes were soluble in polar organic solvents and displayed λ_max ranging between 430 and 456 nm. Upon addition of various acids, the λ_max shifted to higher wavelengths (513–535 nm). In the solid state and in solution, the azo dye‐containing metallocalix[4]arenes reversibly changed colour in the presence of acid and base, indicating their potential use as acid sensors. Cyclic voltammetric studies showed that the iron centres of the metallocalix[4]arenes were reversibly reduced at E_1/2 = −1.49 V. When non‐branching organoiron‐based calix[4]arene were reacted with dithiols, polymers containing calix[4]arenes either in their side chains or main chains were obtained. The polymers possessed weight average molecular weights between 35 000 and 53 000. The polymers were determined to be thermally stable with backbone decomposition occurring above 500 °C.

     

Sorption of azo dyes from aqueous solutions by tetradodecyloxybenzylcalix[4]resorcinarene derivatives

Four water-insoluble tetradodecyloxybenzylcalix[4]resorcinarenes with various functional groups at the upper macrocycle rim (unsubstituted calix[4]resorcinarene 1, carboxylic acid derivative 2, ethyl ester derivative 3 and aminoethylamide derivative 4) were synthesized and tested as sorbents for water-soluble azo dyes methyl orange (MO), acid orange 5 (AO 5) and congo red (CR) by solid–liquid extraction method without background electrolyte. It was observed that the sorption of azo dyes reaches 99% for sorbent 4, which is partial protonated in contact with water and becomes able to electrostatic interactions with the dyes. It was demonstrates that calixresorcinarene 4 has the excellent sorption capacity for AO5 (130.5?mg dye per g of sorbent) due to effective calixresorcinarene—dye association in equal molar ratio mode.     

Determination of manganese in some medicinal plants and their infusions by a catalytic spectrophotometric method

The catalytic effect of manganese (II) on the oxidation of the azo dye 3-Methyl-6-(2-hydroxyethoxy)-2-[2-methoxy-4-N (N, N diethylamino) phenylazo] benzothiazolium methylsulphate, with potassium periodate in the presence of 1,10-phenanthroline in weakly acidic media was studied. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 560 nm. Under the optimum conditions (4 x 10(-5) mol dm(-3) azo dye, 4 x 10(-4) mol dm(-3) potassium periodate, 1 x 10(-4) mol dm(-3) 1,10-phenanthroline, 0.1 mol dm(-3) buffer--pH 3.0, 70 degrees C, 8 min) manganese (II) in the range 0.1-5 ng cm(-3) could be determined by the fixed-time method with a detection limit of 0.035 ng cm(-3). The developed method is highly sensitive, selective, and simple. The method was applied successfully to the determination of total manganese in some medicinal plants and to analyse their infusions for trace amounts of total manganese and free manganese (II) ions without separation.     

Synthesis and study of azo dye compounds: variation of mesogenic behaviour with length of alkyl chains

The mesogenic behaviours of two azo dye liquid crystals, 1 and 4, differ because of the different length of terminal alkyl chains; azo dye 1 shows a SmB phase, azo dye 4 shows nematic and SmA phases during thermal processing. The molecular stackings of these two azo dye liquid crystals are compared on the basis of crystallographic studies to explain such unexpected mesogenic behaviour.     

Soluble polymer-supported catalysts containing azo dyes

[structure: see text] Azo benzene derivatives were incorporated into soluble polymer-bound catalysts by two different approaches. The first was to attach the dye to the polymer-bound catalysts, using the dye as an innocent spectator to study the phase preference, concentration, and recoverability of a catalyst. The second approach used an azo dye as a ligand to form an effective soluble polymer-bound Pd(II) catalyst for Heck reactions.     

Intermolecular interactions in mixtures of dichroic dyes with n-alkyl-4-(4-isothiocyanatophenyl)bicyclo[2,2,2]octanes

On the basis of the polarized absorption spectra, the guest order parameter as a function of temperature for five dichroic azo dyes dissolved in four members (pentyl to octyl) of the homologous series of n-alkyl-4-(4-isothiocyanatophenyl)bicyclo[2,2,2]octanes has been evaluated. Moreover, the influence of the dichroic dye addition on the nematic-isotropic phase transition temperature has been examined. The relation between the molecular geometry of the guest, its orientation efficiency in the nematic host and the clearing temperature of the azo dye-liquid crystal mixtures has been determined. The experimental results have been compared in some detail with calculations performed on the basis of the mean field theory for binary mixtures.     

Synthesis and study of azo dye compounds: variation of mesogenic behaviour with length of alkyl chains

The mesogenic behaviours of two azo dye liquid crystals, 1 and 4, differ because of the different length of terminal alkyl chains; azo dye 1 shows a SmB phase, azo dye 4 shows nematic and SmA phases during thermal processing. The molecular stackings of these two azo dye liquid crystals are compared on the basis of crystallographic studies to explain such unexpected mesogenic behaviour.     

Design and synthesis of novel antimicrobial acyclic and heterocyclic dyes and their precursors for dyeing and/or textile finishing based on 2-N-acylamino-4,5,6,7-tetrahydro-benzo[b]thiophene systems

A series of novel polyfunctionalized acyclic and heterocyclic dye precursors and their respective azo (hydrazone) counterpart dyes and dye precursors based on conjugate enaminones and/or enaminonitrile moieties were synthesized. The dyes and their precursors are based on 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide, 2-ethoxycarbonyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide or 2-phenylcarbamoyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide systems as precursors. The latter compounds were used to synthesize polyfunctional thiophene-, thiazole-, pyrazole, pyridine-, pyrimidine-, oxazine-, as well as acyclic moieties. The dyes and dye precursors were characterized by elemental analysis and spectral methods. All dyes and their precursors were screened in vitro and evaluated for both their antibacterial and antifungal activities. MIC data of the novel dye systems and their respective precursors showed significant antimicrobial activity against most tested organisms. Some compounds exhibited comparable or even higher efficiency than selected standards. Dyes were applied at 5% depth for disperse dyeing of nylon, acetate and polyester fabrics. Their spectral characteristics and fastness properties were measured and evaluated.     

Poly(4-tert-butylstyrene) as a soluble polymer support in homogeneous catalysis

[reaction: see text] Use of soluble poly(4-tert-butylstyrene) (PtBS) as a support in synthesis is demonstrated. These soluble polymers supported catalysts that were used in a monophasic medium. Subsequent separation of the catalysts after reaction was effected either by cooling- or by water-induced liquid/liquid-phase separation. Specific catalysts studied included both phosphine and DMAP nucleophilic catalysts. Low loadings of an azo dye quantified the efficiency of separation and recovery of these catalysts through multiple reaction cycles.     

偶氮基杯芳烃化合物的合成及其偶氮-醌腙互变异构性质

通过芳胺的重氮化-偶合反应合成了8个偶氮基杯芳烃化合物, 其结构经IR, 1H NMR, ESI-MS和元素分析表征. 通过UV-Vis, 1H NMR和IR考察了溶液pH值对所合成化合物5,11,17,23-四[(2-苯并噻唑基)偶氮基]-25,26,27,28-四羟基杯芳烃(3)和5,17-二[(1-萘基)偶氮基]-25,26,27,28-四羟基杯芳烃(4)的偶氮-醌腙互变异构的影响. 结果表明, 随着溶液pH值增加, 醌腙体在偶氮-醌腙互变异构平衡中的比例增加, 当pH≥10时, 几乎全部转变为醌腙体. 特别当溶液pH=-1时, 化合物4可以形成一种大的共轭体系, 使其λmax由477 nm红移至545 nm.     

Birefringence and dichroism of oriented epoxy thermoset films

A series of oriented liquid–crystalline epoxy thin films were prepared by the in situ polymerization of a liquid–crystalline diepoxide, 1,4‐phenylene bis[4‐(2,3‐epoxypropoxy)benzoate], with an aromatic diamine, 4,4′‐diaminobiphenyl, in a 7.0‐T magnetic field. The birefringent measurements of the oriented films were made from 543.5 to 830 nm. In this range, the values of birefringence (Δn) range from 0.155 to 0.130. When they are extrapolated to the microwave region, Δn = 0.105. The dichroism of a guest azo dye, 4‐(4‐nitrophenylazo)‐3‐hexyloxyaniline, in the oriented thin films was examined in the visible region. From the results, the order parameter of the polymer was calculated to 0.65 by extrapolating the concentration of the guest azo dye to zero. The guest azo dye compound does not affect the birefringence. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 915–919, 2001     

Synthesis of （p-Formylphenyl）azo Calix[4]arenes

Five novel azo calix[4]arenes were reported. The p-aminobenzaldehyde was diazotized with sodium nitrite in aqueous hydrochloride solution. Mono-, bis-, tris- and tetrakis(p-formylphenyl)azo calix[4]arenes (including proximal and distal isomers) were obtained respectively by diazo-coupling in different molar ratio to calix[4]arene(1) under pH=7.5--8.5 at 0-5℃. All (p-formylphenyl)azo calix[4]arenes were characterized by ^1H NMR, ^13C NMR, IR, MS (ESIMS) spectroscopies and elemental analysis.     

Preparation of poly(2‐anilinoethanol) containing azobenzene group under electrical field and its liquid crystalline properties investigation

In this project, 2‐[N‐ethyl‐N‐[4‐[(4′‐nitrophenyl)azo]‐phenyl]amino]ethanol (Disperse Red‐I) was prepared by adding of (N‐ethyl‐2‐anilinoethanol) with the salt diazonium p‐nitroaniline. The main mesogenic liquid crystalline (LC) 2‐[N‐ethyl‐N‐[4‐[4′‐nitrophenyl)azo]‐phenyl]amino]ethyl‐3‐chloro propionate (Disperse Red‐II) was synthesized by reaction of disperse Red I and 3‐chloropropanoeic acid at the alkaline condition. Then 2‐anilinoethyl‐3‐chloropropionate‐{2‐[ethyl[4‐[(4′‐nitrophenyl)azo]phenyl]amino] ethanol}, (2AECP‐Red‐I) was prepared via reaction of disperse red‐II and 2‐anilinoethanol. On the other hand, poly 2‐anilinoethyl‐3‐chloropropionate‐{2‐[ethyl[4‐[(4′‐nitrophenyl)azo]phenyl]amino]ethanol} and poly(2AECP‐Red‐I) have been synthesized by polymerization of 2AECP‐Red‐I in two separate schemes. These include polymerization in the absence of electric field (EF) and polymerization under different EFs. A comparison of the results reveals that the polymer produced under electric field is more linear, regular in shape with high electrical conductivity, as well as good LC behavior with semectic texture. The resulted monomer and poly(2AECP‐Red‐I) are characterized by using Fourier transform infrared and ultraviolet–visible and were studied by thermogravimetric analysis and differential scanning calorimetry. Scanning electron microscopy images supported the formation of poly(2AECP‐Red‐I) and showed morphology feature and homogeneous structure on poly(2AECP‐Red‐I). Electrical conductivity of poly(2AECP‐Red‐I) has been studied by four‐point probe method. Copyright © 2014 John Wiley & Sons, Ltd.     

5,11,17,23-Tetrakis[(p-carboxyphenyl)azo]-25,26,27,28-tetra-hydroxy Calix[4]arene: Crystal Structure and pH Sensing Properties

Treatment of 5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]‐25,26,27,28‐tetrahydroxy calix[4]arene ( 2 ) with HCl in DMF or NaOH in MeOH produced 5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]‐25,26,27,28‐tetrahydroxycalix[4]‐arene·4DMF (2·4DMF) and 5,11,17,23‐tetrakis[(p‐carboxyphenylsodium)azo]‐25,26,27,28‐tetrahydroxycalix[4]‐ arene ( 3 ), respectively, which were characterized by elemental analysis, IR, UV‐vis, ¹H NMR and ¹³C NMR. An X‐ray analysis of 2·4DMF revealed that its calix[4]arene core adopts a flattened cone conformation in which opposed phenyl groups take parallel or sharply inclined positions. The intra‐ and intermolecular hydrogen‐bonding interactions and the π···π interactions form a 2D hydrogen‐bonded wavelike network. Compound 2 had a unique reversible color change in a wide pH range from 1 to 13.5 and showed interesting pH sensing properties.     

Novel Disubstituted Calix[4]arenes Containing Chromogenic Groups on the Lower Rim: Synthesis,Structural Identification,and Absorption Properties

5,11,17,23‐Tetra‐tert‐butyl‐25,26,27,28‐tetrahydroxycalix[4]arene and 25,26,27,28‐tetrahydroxycalix[4]arene were synthesized based on previous literature. Firstly, several azo dyes were synthesized, and then, these dyestuffs were chlorinated through reaction with thionyl chloride. Secondly, the azo compounds bonded with methylene chloride and reacted with 25,26,27,28‐tetrahydroxycalix[4]arene, and then, six novel disazocalix[4]arene derivatives 4 ( a – f ) were achieved. Their structures were characterized as Fourier transform infrared, ¹H‐NMR, and elemental analysis. In this study, we investigated the solvatochromic properties of the compounds and the acid–base effect on their ultraviolet–visible absorption by using six solvents.