邻硝基苯偶氮-α-萘酚合锌的合成与表征

偶氮染料是优良的二阶非线性光学生色分子,由于偶氮增感染料在聚乙烯咔唑为主体的光折变染料复合体中起着十分重要的作用。为了进一步研究不同的偶氮增感染料对光折变性能的影响,笔者在合成偶氮化合物的基础上又合成了偶氮染料过渡金属配合物,并对它们进行了初步的结构表征。     

邻硝基苯偶氮-α-萘酚合铬的合成与表征

偶氮染料是优良的二阶非线性光学生色分子,由于偶氮增感染料在聚乙烯咔唑为主体的光折变染料复合体中起着十分重要的作用。为了进一步研究不同的偶氮增感染料对光折变性能的影响,我们在合成偶氮化合物的基础上又合成了偶氮染料过渡金属配合物,并对它们进行了初步的结构表征。     

1-正-丁氧基-2，5-二甲基-4（4’-硝基苯基偶氮）苯的合成及表征

聚合物光折变材料是将光电功能和电光功能有机结合而呈现光折变效应的一种多功能组分材料。国内研究以偶氮分子作为非线性光生色团分子的聚合物光折变材料逐渐增多，但对1-正-丁氧基-2,5-二甲基-4-（4’-硝基苯基偶氮）苯非线性光生色团分子的制备及其表征鲜见报道。     

生色团4-正戍烷氧基-氰基二联苯的合成及表征

光折变效应是在光学非线性材料中，由于电荷的再分布，引起的折射指数的空间调制。具有光折变效应的聚合物在光信息处理、高密度光存储、光学相位共轭等诸多领域已广泛应用，得到科学工作者极大关注。     

金属卟啉-液晶超分子化学、光学特性综述

光信息处理和海量存储的需要合适的光信息存储器件,基于各种材料的光信息存储器主要包括无机晶体、有机聚合物和纯液晶等。基于无机晶体等的光信息存储器则需要数千伏的工作电压和数百毫瓦/平方毫米的光记录功率,衍射效率最高为20-30%。液晶是广泛使用的显示器材。与偶氮苯系列和C60纳米材料系列相比,掺杂金属卟啉的液晶光折变具有突出优点,可以实现在弱记录光、低电压下工作的低功耗、长时间记忆,是新型光信息存储器件,其竞争力远远超过传统的无机光折变晶体和目前的有机光折变材料。     

光折变晶体的现状和发展

本文简要叙述了光折变材料,包括光折变效应的基本原理、材料的分类、不同材料各自的优点和缺点以及光折变材料的应用。讨论了阻碍原型器件转化为商品器件的几种因素。提出了克服这些障碍的途径和发展新的光折变材料的方向。     

光折变光子晶格局域光的角度要求研究

实验中我们用与在LiNbO_3:Fe晶体中写入光折变光子晶格时相同频率的光照射到LiNbO_3晶体写入光折变光子晶体的区域,在入射光与光折变光子晶格周期方向成较小的角度(小于12°)时,观察到了光折变光子晶格对光的局域现象。利用光在分层介质中传播时的传输特性,理论上计算了光在光折变光子晶格中传播时的反射率R与入射角度θ(入射光束与光子晶格周期方向的法线所成角度)之间的关系。发现理论计算结果与实验结果是相一致的。     

偶氮染料偶氮苯-4-磺酸钠的合成实验

以对氨基苯磺酸和苯胺为底物 ,合成了偶氮苯 - 4-磺酸钠。用UV/Vis光谱、FT -IR光谱对合成产物进行了鉴定 ,表明产物结构正确。为合成类似结构的偶氮染料提供了实验依据     

掺杂对铌酸锂光折变响应速度的提高

在ＬｉＮｂＯ３晶体掺入Ｔｂ离子，可提高晶体的光折变响应速度。Ｔｂ：Ｆｅ：ＬｉＮｂＯ３晶体既保留了Ｆｅ：ＬｉＮｂＯ３良好的光折变性能，同时其光折变响应时间大大缩短，可达十几秒，光折变响应速度的提高。可归结为晶光电导的增大，使得晶体内空间电荷场的建立更加迅速。     

胶合透镜法在LiNbO3：Fe晶体中制作光折变光子晶格

研究了一种制作光折变光子晶格的新方法——胶合透镜法。利用此方法在LiNbO3：Fe晶体中成功的制作了一维和二维光折变光子晶格。同时,对实验现象和实验原理进行分析得到,此种方法不仅可以得到较大面积的干涉区域从而可以制作出较大面积光折变光子晶格,此外这种方法可以实现晶格周期的连续调节,进而可以根据需求制作不同周期的光折变光子晶格。在实验中也验证了这种方法的优点与可行性,这对光子晶格的制作与研究有一定的意义。     

New azo ligands containing azomethine groups in the pyridazine-based chain: Synthesis and characterization

Five, novel pyridazine-based azo chromophores were synthesized by the condensation reaction of 3,6-bis((aminoethyl)thio)pyridazine with 5-(4-X-phenyl)-azo-salicylaldehyde (X = NO₂, Cl and Et), 5-(2,4-di-Cl-phenyl)-azo-salicylaldehyde and 5-(3,4-di-Cl-phenyl)-azo-salicylaldehyde. The dyes were characterized by elemental analysis, thermal analyses, IR, UV–vis, NMR and mass spectroscopy. Spectral characteristics of the dyes were investigated in four organic solvents of differing polarity; thermal studies indicate that the framework of dyes is stable up to 220 °C. Complexation of the azo dyes with Cu(II) gave subtle changes in their absorption spectra.     

Polarographic and voltammetric investigation of 6′-butoxy-2,6-diamino-3,3′-azodipyridine

Voltammetric and polarographic reduction on a hanging mercury electrode in aqueous-ethanol medium was performed for the 6′-butoxy-2,6-diamino-3,3′-azodipyridine by using SWV, DPP, DCP and CV techniques. Electrochemical behaviour of the azo compound has been investigated depending on ethanol–water ratio. From the polarographic and voltammeric data, electrochemical reduction mechanism has been suggested. Adsorption effect of the azo compound was investigated at different pH values. Optimum conditions are given for its polarographic and voltammetric determination. The limit determination using an HMDE was around 2.72 × 10⁻⁹ M for SWV.     

Polyurethane–epoxy based azopolymers: Influence of chemical structure over photoinduced birefringence

A comparative study of the influence of the competitive reactions that can take place in epoxy–isocyanate based azo systems over optical behavior was developed.Diverse disperse red 19 (DR 19) azo urethane oligomers (PUs) were synthesized and characterized using size exclusion chromatography (SEC), Fourier transform infrared (FTIR), and UV–visible spectroscopy. Based on these urethane oligomers, epoxy-PU networks having isocyanurate and oxazolidone rings in their structures were prepared in different isocyanate/epoxy stoichiometric ratios, r = eq. NCO/eq. epoxy (0.5, 1, and 2).Photoinduced anisotropy (Δn), remnant birefringence (RB) and dichroism were measured for the resulting polymers and evaluated as function of their T_gs and chemical structures. Final materials exhibited very high values of Δn and RB being promised materials for using in optical storage information devices.     

Syntheses and investigation of thermal properties of copper complexes with azo-containing Schiff-base dyes

In the present study a series of azo dyes: 5-((4-pentyloxyphenyl)azo)-salicylaldimine-N-R (R = phenyl, 4-methoxyphenyl, cyclohexyl) and related copper(II) bis chelates have been synthesized and characterized by IR, NMR, mass spectroscopies and elemental analyses. The thermal stability of free ligands and related copper(II) bis(chelate) was studied by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The differences in the thermal stability were related to the structure of free ligands and copper complexes and decomposition products were characterized according to their X-ray diffraction pattern.     

Kinetic investigation of an azo dye oxidation by hydrogen peroxide in aqueous surfactant solution

In this study, the oxidation of resorcinol based an azo dye, 5-methyl-4-(2-thiazolylazo)resorcinol (5-Me-TAR) by hydrogen peroxide has been investigated from kinetic, spectroscopic and thermodynamic point of view to examine the influence of a cationic surfactant such as cetylpyridiniumchloride (CPC). Activation energy (298.15–313.15 K) and entropy (298.15 K) of the reaction were calculated as 67 kJ/mol and −72 J mol⁻¹ K⁻¹ in borate buffer, respectively. However, the addition of CPC into 5-Me-TAR solutions at different pH values always reduced the intensity of its azo form, the intensity of its hydrazone form increased. The oxidation of dye proceeds via perhydroxyl anion and hydrazone tautomeric form and oxidation rate was accelerated by the presence of CPC either in micellar or premicellar regions.     

A novel Wells–Dawson polyoxometalate-based metal–organic framework constructed from the uncommon in-situ transformed bi(triazole) ligand and azo anion

A novel Wells–Dawson polyoxometalate (POM)-based metal–organic framework (MOF) constructed from bi(triazole) ligand and azo anion, namely, [Ag₁₃(L)₆(N₂)(HP₂W₁₈O₆₂)] (1) (HL = 4-(1 H-1,2,4-triazol-3-yl)-2 H-1,2,4-triazolyl) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectra, PXRD analysis. In compound 1, the rigid bi(triazole) ligands connected Ag^I ions to construct a 2D metal–organic layer, which was further extended by azo anions forming a 3D framework. The Wells–Dawson type [P₂W₁₈O₆₂]^6 − anion as a multidentate inorganic ligand coordinated with the Ag^I ions, consolidating the 3D MOF. The L ligands and azo anions were in-situ transformed from a bi(triazole) derivative, which has never been observed in previous reports. In addition, the electrocatalytic and photocatalytic properties of compound 1 have been investigated.     

Synthesis and characterization of photoactive poly(arylene ether sulfone)s containing azobenzene moieties in their main chains

A series of azobenzene functionalized poly(arylene ether sulfone)s (azo-PAESs) has been synthesized via nucleophilic aromatic substitution polycondensation, and azobenzene chromophores could be introduced into the polymer main chains by copolymerization from azo-monomers. These main chain type azo-PAESs have high glass transition temperatures and good thermal stability. Exposed to an interference pattern laser beam, spin-coated films of the azo-PAESs can form clear and stable surface relief gratings (SRGs). These SRGs show increased thermal stabilities with the content of azo moieties and cannot be fully removed until the temperature increases to 300 °C for azo-PAESs with a content of azo segments above 50%.     

Preparation of high active nanometer TiO2 sonocatalyst by partial transition crystal in hydrogen peroxide solution under ultrasonic irradiation

The transition crystal nanometer TiO₂ sonocatalyst with high sonocatalytic activity was prepared utilizing the method of ultrasonic irradiation in hydrogen peroxide solution. The sonocatalytic activity of transition crystal nanometer TiO₂ powder was validated through the degradation of acid red B and azo fuchsin solutions by ultrasonic irradiation, respectively. The results show that the sonocatalytic activity of the transition crystal nanometer TiO₂ powder is obviously higher than ones of both original nanometer rutile and anatase TiO₂ powders. The degradation ratios of acid red B and azo fuchsin in the presence of the transition crystal nanometer TiO₂ catalyst surpass 96.5% and 85.3% within 40 min ultrasonic irradiation, respectively. At the same conditions, the degradation ratios are 62.5% and 45.0% in the presence of original nanometer anatase TiO₂ powders, 73.5% and 59.5% in the presence of original nanometer rutile TiO₂ powders, respectively, while the corresponding degradation ratios are only 29.8% and 14.2% in the absence of any TiO₂ catalyst, respectively. The degradation processes of both acid red B and azo fuchsin solutions are the pseudo-first-order reaction.     

Effect of heterojunction on photocatalytic properties of multilayered ZnO-based thin films

In the present study, the effects of the heterojunctions on the optical and structural characteristics and the resulting photocatalytic properties of multilayered ZnO-based thin films were investigated. The junctions were composed of semiconducting ZnO nano-porous films coated on the In₂O₃ and SnO₂ counterpart layers. The multilayered ZnO films based on the triple-layered Ag-doped indium oxide (AIO)/tin oxide (TO)/zinc oxide (ZnO), indium oxide (IO)/Ag-doped tin oxide (ATO)/zinc oxide (ZnO), indium oxide (IO)/tin oxide (TO)/zinc oxide (ZnO) and tin oxide (TO)/indium oxide (IO)/zinc oxide (ZnO) have been fabricated by subsequent sol–gel dip coating. Their structural and optical properties combined with photocatalytic characteristics were examined toward degradation of Solantine Brown BRL (C.I. Direct Brown), an azo dye using in Iran textile industries as organic model under UV light irradiation. Effects of operational parameters such as initial concentration of azo dye, irradiation time, solution pH, absence and presence of Ag doping and consequent of sublayers on the photodegradation efficiencies of ZnO nultilayered thin films were also investigated and optimum conditions were established. It was found that the photocatalytic degradation of azo dye on the composite films followed pseudo-first order kinetics. Photocatalytic activity of AIO/TO/ZnO interface composite film was higher compared with other films and the following order was observed for films activities: AIO/TO/ZnO > IO/TO/ZnO > ATO/IO/ZnO > TO/IO/ZnO. Differences in the film efficiencies can be attributed to differences in crystallinity, interfacial lattice mismatch, and surface morphology. Besides, the presence of Ag doping between layers that may act as trap for electrons generated in the ZnO over layer thus preventing electron–hole recombination.     

Solar-light-induced photocatalytic decomposition of two azo dyes on new TiO2 photocatalyst containing nitrogen

The photocatalytic decolourisation of two azo dyes—Reactive Red 198 and Direct Green 99—in an aqueous solution by the artificial visible light radiation was investigated. The industrial metatitanic acid (H₂TiO₃) obtained directly from the sulphate technology installation was N-doped and used as photocatalyst. H₂TiO₃ was calcinated at different temperatures, ranging from 300 to 500 °C, for 4 or 20 h, respectively, in an ammonia atmosphere. The UV–vis/DR spectra of the modified catalysts exhibited an additional maximum in the vis region (λ ≈ 476.8 nm, E_G = 2.60 eV for catalysts calcinated for 4 h and λ ≈ 479.5 nm, E_G = 2.59 eV for catalysts calcinated for 20 h, which may be due to the presence of nitrogen in TiO₂ particles. The chemical structure of the modified photocatalysts was investigated using FTIR/DRS spectroscopy and the presence of nitrogen was confirmed. A photocatalytic activity of the investigated catalysts was determined on the basis of a decomposition rate of azo dyes. The decomposition of Reactive Red 99 increased with increasing the calcination temperature of photocatalysts, whereas the activity of the prepared photocatalysts towards Direct Green 198 degradation was as follows: 300–20 h < 400–20 h < 500–20 h < 300–4h < 400–4 h < 500–4 h. Both, the calcination time and temperature had no influence on the amount of nitrogen-doped into TiO₂ structure. The inversely proportional linear dependence between the decomposition rates of azo dyes and the intensity of the band attributed to the hydroxyl groups for both dissociated water and molecularly adsorbed water was observed. With increasing temperature of calcinations, the amount of the hydroxyl groups decreased, whereas the decomposition of azo dyes increased.