聚合物电致发光材料及其发光颜色调节的研究进展

聚合物电致发光材料已成为功能材料研究领域的一个热点.与无机材料和有机小分子材料相比,聚合物发光材料具有来源广泛、易加工成型、通过分子结构设计可调节发光颜色等优点,成为制备大面积、低成本、全色柔性显示器件的首选材料.本文介绍了聚合物发光材料的发光机理及调节发光颜色的常用方法,综述了聚对苯乙炔类、聚对苯类、聚芴类等多种共轭聚合物发光材料的合成及发光颜色调节的研究现状,并对聚合物发光材料的发展趋势以及聚合物电致发光器件的制备进行了评述和展望.     

带有PPE侧链的聚合物的合成及其发光性质的研究

有机共轭聚合物发光材料成为近年来多学科交叉研究的热点[1~3]。作为共轭聚合物之一,聚对苯乙炔(Poly(p-phenyleneethynylene))(PPE)具有较高的电子亲合势、电致发光效率、对微量水和氧气稳定等优点,近年来受到很大的关注[4~7]。PPE分子链间通过π-π堆积效应(π-πstacking)在     

蒽端基聚对苯亚乙炔的发光性能

报道了一种新的蒽端基聚对苯亚乙炔的合成与发光特性,分别考察了聚合物 P2的紫外吸收,荧光发射和电致发光光谱。结果表明,在聚对苯亚乙炔主链末端引 入蒽基团可改变其有效共轭长长及发光颜色,合成的模型小分子可证明这一点。电 致发光器件ITO/P2/Al在600 nm处发红光。     

可溶性聚对苯乙炔的合成及其电致发光性能

采用紫外－可见光谱跟踪用直接聚合法制备可溶性的聚对苯乙炔衍生物的反应过程,结果表明反应仍然经历了生成前聚物的过程。控制反应条件使聚合反应首先生成前聚物,在前聚物烯化反应阶段加入起增溶作用的长链醇,得到了具有良好的溶解性的、主链中含非共轭链段的聚对苯乙炔衍生物。用该聚合物制备的电致发光器件,在５－６Ｖ电压驱动下发光,发光峰位于５８０ｎｍ左右。     

聚对苯撑乙炔的合成及光谱性能-共轭主链被间位苯环阻隔

报道了一种阻隔型聚对幕撑乙炔((PPE)的合成与电致发光特性,合成的模型小分子证明,在聚对苯撑乙炔(PPV)主链引入间位幕环,可阻隔PPV的有效共轭长度,改变其发光颜色,研究了电致发光暑件ITO／m-PPE／Al的电致发光特性。     

一种主链含有离子导电性链段的功能发光共聚物

1990年英国剑桥大学的Ｂｕｒｒｏｕｇｈｅｓ等人[1 ]使用聚对苯乙炔 (ＰＰＶ)成功的制备了第一个聚合物电致发光二极管 (ＬＥＤ)的报道引起了电致发光领域世界范围内的研究高潮 ,特别是 1 995年裴启兵等人[2 ,3] 发明的电化学发光电池 (ＬＥＣ)的技术更进一步地推动了聚合物发光器件商业化的步伐。ＬＥＣ相对于ＬＥＤ具有很多优势[4] ,但是ＬＥＣ中一个关键技术是要克服共轭非极性荧光聚合物与非共轭极性离子传导聚合物的相分离问题从而制备高质量的发光薄膜 .目前较好的解决方法是将极性的离子传导侧链接枝在荧光聚合物的主链上而得到直接…     

去卤缩聚法合成蓝色电致发光聚合物聚（2,5—二庚基）对苯乙炔

利用双卤甲基苯衍生物在强碱诱导下的缩合反应，合成了共轭态可溶的聚对苯乙炔，并利用ＩＲ，ＵＶ－Ｖｉｓ，＾１Ｈ－ＮＭＲ，ＴＧＡ等对聚合物结构与性能进行了有征，其Ｎｎ＝０．４８×１０＾４。电致发光器件的发光峰值波长为４８６ｎｍ，起亮电压为２２Ｖ。     

刚柔嵌段共轭聚合物自组装体系*

刚柔嵌段共轭聚合物的自组装是超分子化学研究的热点之一。本文综述了近年来刚柔嵌段共轭聚合物自组装体系研究进展。根据共轭刚性段的不同分类进行阐述,综述了聚芴,二（苯乙烯）-蒽,聚对苯撑,聚对苯乙烯撑,聚对苯撑乙炔,聚（2,5-苯甲酮）,聚噻吩,聚苯基喹啉等作为刚性链段的刚柔嵌段共轭聚合物自组装体系,介绍了刚柔嵌段共轭聚合物的合成和光物理性质;重点评述了刚柔嵌段共轭聚合物在不同溶剂、浓度、温度等条件下自组装形成一维、二维以及三维的周期性微结构,且具有方便的可控性。概括了刚柔嵌段共轭聚合物自组装体系广阔的应用前景,尤其在光电器件领域有着潜在的应用价值。最后展望了刚柔嵌段共轭聚合物自组装体系研究和发展的方向。     

阻隔型聚对亚苯乙炔电致发光特性研究

报道了一种新的阻隔型聚对亚苯基乙炔的合成与电致发光特性,在聚对亚苯基乙炔主链引入已基碳链,可阻隔聚对亚苯基乙炔的有效共轭长度,改变发光颜色,合成的模型小分子可证明这一点,利用X射线衍射研究了退火前后阻隔型聚对亚苯基乙炔薄膜的晶态变化,研究了电致发光器件ITO/PPE2/Al的电致发光特征。     

阻隔型聚对亚苯乙炔电致发光特性研究

报道了一种新的阻隔型聚对亚苯基乙炔的合成与电致发光特性,在聚对亚苯基乙炔主链引入已基碳链,可阻隔聚对亚苯基乙炔的有效共轭长度,改变发光颜色,合成的模型小分子可证明这一点,利用X射线衍射研究了退火前后阻隔型聚对亚苯基乙炔薄膜的晶态变化,研究了电致发光器件ITO/PPE2/Al的电致发光特征。     

Derivatives of 3,4-dihydro-β-carboline-3-carboxylic acid from c-terminal tryptophan-containing peptides. Synthesis and properties

C-Terminal tryptophan containing peptides have been converted into 1-peptidyl-3,4-dihydro-β-carboline-3-carboxylic acids by acid catalyzed isomerization of their azlactone derivatives. The main properties of these abnormal peptides are a strong absorption around 360 nm an intense yellow fluorescence and ability to generate reactive carbanions when dissolved in basic media. This tryptophan conversion takes place with high yield and is of general applicability.     

Phosphorus-ylides: powerful substituents for the stabilization of reactive main group compounds

Phosphorus ylides are 1,2-dipolar compounds with a negative charge on the carbon atom. This charge is stabilized by the neighbouring onium moiety, but can also be shifted towards other substituents thus making ylides strong π donor ligands and hence ideal substituents to stabilize reactive compounds such as cations and low-valent main group species. Furthermore, the donor strength and the steric properties can easily be tuned to meet different requirements for stabilizing reactive compounds and for tailoring the properties and reactivities of the main group element. Although the use of ylide substituents in main group chemistry is still in its infancy, the first examples of isolated compounds impressively demonstrate the potential of these ligands. This review summarizes the most important discoveries also in comparison to other substituents, thus outlining avenues for future research directions.

The application of ylide substituents as strong donor ligands for the stabilization of reactive main group compounds with unusual properties and reactivities is discussed.     

Chemical oxidative polymerization of safranines

Phenosafranine and safranine have been oxidized with ammonium peroxydisulfate in acidic aqueous solution. The oxidative coupling of both safranines was proved by gel permeation chromatography demonstrating the presence of oligomeric chains of mass-average molar masses 6500 and 4500 g mol-1 for polyphenosafranine and polysafranine, respectively. A theoretical study of the mechanism of safranine and phenosafranine polymerization was based on the MNDO-PM3 semiempirical quantum chemical computations of the heat of formation of dimeric reaction intermediates, taking into account solvation effects. The study of the redox properties of the hydrated safranines and their reactive species shows that nitrenium cations are the main reactive species generated by the oxidation of the parent safranines with a two-electron oxidant, peroxydisulfate, in the initiation phase. The dominant dimers of safranines are formed by N-C coupling reactions between nitrenium cations and the parent safranines. The main coupling reactions of phenosafranine are N-C2 (C8) and N-C4 (C6); N-C4 (C6) is the dominant coupling mode for safranine. The molecular structure of oligosafranines has been studied by FTIR, Raman, and UV-vis spectroscopies. Besides prevalent unoxidized monomeric units, polymerization products of safranines contain also the iminoquinonoid and newly formed fused phenazine units.     

Functionalization of cellulose nanofiber mats with phthalocyanine for decoloration of reactive dye wastewater

A versatile method is reported for the preparation of cellulose nanofiber mats immobilized with cobalt tetraaminophthalocyanine (CoPc). This functionalized cellulose nanomaterial was used as an efficient catalyst for the decoloration of reactive dye wastewater. Cellulose acetate was electrospun into nanofiber mats (CA-NM), hydrolyzed with KOH, and then oxidized by NaIO₄ to generate aldehyde groups for CoPc immobilization. The functionalization processes on the nanofiber mats were monitored by attenuated total reflection Fourier transform infrared spectroscopy (ATR/FT-IR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscope (FESEM). We found these CoPc-functionalized nanofiber mats (CoPc-NM) have high adsorption capacity for reactive dye from synthetic wastewater, which enhances the catalytic oxidation rate of reactive dye when H₂O₂ is present as oxidant. More than 90% of reactive red X-3B can be eliminated by CoPc-NM/H₂O₂ in 90?min. UV and GC-MS analyses indicate the catalytic oxidation not only breaking the azo linkages but also decomposing the aromatic parts of reactive red X-3B, and the main products are biodegradable aliphatic acids, such as fumaric acid, succinic acid, and maleic acid, etc. Repetitive measurements also show that this CoPc-NM is quite stable and remains efficient with no obvious decrease of catalytic activity.     

Products and kinetics of the heterogeneous reaction of suspended vinclozolin particles with ozone

Vinclozolin is a widely used fungicide that can be released into the atmosphere via application and volatilization. This paper reports an experimental investigation on the heterogeneous ozonation of vinclozolin particles. The ozonation of vinclozolin adsorbed on azelaic acid particles under pseudo-first-order conditions is investigated online with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The ozonation products are analyzed with a combination of VUV-ATOFMS and GC/MS. Two main ozonation products are observed. The formation of the ozonation products results from addition of O(3) on the C-C double bond of the vinyl group. The heterogeneous reactive rate constant of vinclozolin particles under room temperature is (2.4 ± 0.4) × 10(-17) cm(3) molecules(-1) s(-1), with a corresponding lifetime at 100 ppbv O(3) of 4.3 ± 0.7 h, which is almost comparable with the estimated lifetime due to the reaction with atmospheric OH radicals (～1.7 h). The reactive uptake coefficient for O(3) on vinclozolin particles is (6.1 ± 1.0) × 10(-4).     

Reaction Pathways and Redox States in α-Selective Cobalt-Catalyzed Hydroborations of Alkynes

Cobalt(II) alkyl complexes supported by a monoanionic NNN pincer ligand are pre-catalysts for the regioselective hydroboration of terminal alkynes, yielding the Markovnikov products with α:β-(E) ratios of up to 97:3. A cobalt(II) hydride and a cobalt(II) vinyl complex appear to determine the main reaction pathway. In a background reaction the highly reactive hydrido species specifically converts to a coordinatively unsaturated cobalt(I) complex which was found to re-enter the main catalytic cycle.     

异丁烯二聚反应

由于甲基叔丁基醚(MTBE)对水源的污染,它作为汽油添加剂的应用受到环保限制,并对其生产和应用前景带来消极影响。MTBE经裂解、二聚和加氢生产异辛烷成为国外现有MTBE装置转产的主要途径。本文对异丁烯二聚催化剂、反应活性位、机理及动力学研究成果进行了综述,试图解释在异丁烯二聚时,加入的叔丁醇对二聚反应选择性提高的作用机理,为今后二聚反应的研究提供参考。     

Reactive Molecular Dynamics Simulation on Thermal Decomposition of n-Heptane

The thermal decomposition of n-heptane is an important process in petroleum industry. The theoretical investigations show that the main products are C₂H₄, H₂, CH₄, and C₃H₆, which agree well with the experimental results. The products populations depend strongly on the temperature. The quantity of ethylene increases quickly as the temperature goes up. The conversion of n-heptane and the mole fraction of primary products from reactive molecular dynamic and chemical kinetic modeling are compared with each other. We also investigated the pre-exponential factor and activation energy for thermal decomposition of n-heptane by kinetic analysis from the reactive force field simulations, which were extracted to be 1.78×10¹⁴ s^-1 and 47.32 kcal/mol respectively.     

Reactive Groups,Spacer Groups and Functional Groups in Macromolecular Design

Several aspects of modern design of macromolecular architecture are discussed: the influence and importance of functional groups which often dominate the characteristics of the macromolecular structure; the importance of the spacer groups that provide flexibility and allow the functional group to act independently from the main chain when the functional group is attached to the main chain.

Examples are given for the synthesis of reactive, telechelic polymers, for polymerizability of monomers whose polymerizable group is separated from the functional group by a flexible methylene spacer, and the reactivity of functional groups separated from the main chain by a spacer group.     

Gefriergetrocknete Acetate von Sr und Fe als reaktive Vorläufer für komplexe Eisen-Strontium-Oxide

The thermal decomposition of reactive freeze-dried acetate precursors for Sr-Fe-oxides was investigated by means of DTA, TG, mass spectroscopy and X-ray powder diffractometry. In the case of decomposition of Fe(III)-m-oxo-acetate four superimposed main steps are characterized as release of (a) H₂O, (b) acetic acid and ketene (c) methane, ketene and CO₂ and (d) acetone and CO₂. On careful decomposition, single phase γ-Fe₂O₃ can be formed. The decomposition of freeze-dried mixed Fe-Sr-acetates reflects some aspects of the single acetates, but also an interaction between the components. The interactions result in a lower decomposition temperature of Sr-acetate (release of acetone and formation of SrCO₃). The decomposition temperature of SrCO₃ in the reactive mixture is also lowered. The simultaneous decomposition of SrCO₃ and its reaction with the Fe-component results directly in the formation of the expected complex Sr-Fe-oxide. This revised version was published online in August 2006 with corrections to the Cover Date.