一种双功能光折变模型分子的光电导性质

咔唑衍生物及含咔唑基团的聚合物由于在光信息传导、全息照相和光折变等高科技领域的潜在应用前景而越来越受到重视［１～３］,大量有机光折变材料已被合成．其中一些含有咔唑成分的光折变材料具有很优异的性能．１９９４年,一种具有低玻璃化温度的ＰＶＫ掺杂体系的净增益参数达到２２０ｃｍ－１,而衍射效率也近似达到１００％．这一结果超过了已知的绝大多数无机物［２］．大多数咔唑衍生物及含咔唑基团的聚合物都具有良好的光电导性质,并且主要以空穴传导为主．但它们的迁移率和机理由于引入不同的侧基和掺杂物出现很大差别［４～６］…     

含偶氮苯的咔唑类双功能光折变聚合物的合成及表征

通过后重氮偶合方法制备了一系列不同生色团含量的咔唑类双功能光折变聚合物，并用IR、^1H-NMR、UV-vis、DSC以及GPC等对聚合物进行了分析和表征。IR和UV-vis谱图显示偶氮苯基团已接到咔唑环上。UV-vis结果表明：反应时间对该反应的影响非常大，当反应时间从6h增加到60h时，聚合物中生色团的含量从13.5%升高到66.7%。GPC结果显示后重氮偶合法比常规方法得到的该类聚合物的分子量明显提高。DSC结果显示聚合物的玻璃化转变温度随偶氮苯含量的增加而升高。     

全功能光折变聚合物的分子设计及进展

介绍了全功能光折变聚合物的分子设计和研究进展,分析了各种结构对聚合物光折变性能的影响,展望了今后在此领域的研究方向。     

后重氮偶合法制备咔唑类光折变聚合物

生色团;后重氮偶合法制备咔唑类光折变聚合物     

光折变聚合物的研究进展

介绍了光折变聚合物的基本概念、基本特性及其分类情况,对每一类聚合物的发展现状及其存在的问题作了较为详细的阐述,并展望了其今后发展的方向。     

掺钕铌酸锂晶体光折变效应的研究

钕掺杂的铌酸锂Nd:LiNbO_3(以下简写为Nd:LN)晶体是光折变晶体,以Nd:LN为基,分别掺入MgO和CeO_2,生长出Nd,Mg:LN和Nd,Ce:LN晶体。其中Nd,Mg:LN晶体的光折变阈值比Nd:LN提高了二个数量级,抗光损伤能力增强,可作为自倍频激光介质。Nd,Ce:LN晶体的光折变灵敏度比Nd:LN晶体提高了一个数量级,非线性光学性能好。通过光折变阈值和光电导的测量和研究,对钛掺杂的铌酸锂晶体光折变产生的机理,以及Mg和Ce离子在其中的影响作用进行了讨论。     

Ce：Fe：LiNbO3晶体光折变温度增强效应的研究

在ＬｉＮｂＯ３中掺入ＣｅＯ２和Ｆｅ２Ｏ３，生长了Ｃｅ：Ｆｅ：ＬｉＮｂＯ３晶体，在２０￣１２０℃范围内，研究晶体的二波耦合指数增益系数ｒ和四波混频相位共轭反射率Ｒ。随着温度的升高，ｒ和Ｒ以及响应速度等指标都有提高，这是由于晶体内扩散场随温度升高而增大，导致晶体光折变效应增强。在５５、７１和１１０℃附近，指数增益系数ｒ和相位共轭反射率Ｒ出现异常增大，这与该温度下晶体发生结构相变有关。     

含咔唑生色团的聚磷腈的合成与表征

通过后重氮偶合方法制备了一种含咔唑双功能生色团的聚磷腈光折变高分子,并用1H-NMR3、1P-NMRI、R、UV-vis、GPC以及DSC、TG等测试手段对聚合物进行了分析和表征。1H-NMR、IR、UV-vis谱图表明对硝基偶氮苯基团连接在咔唑环上。31P-NMR谱图上的单峰说明聚二氯磷腈分子链上的氯已经全部被咔唑基团取代,而且后功能化反应条件没有破坏磷腈主链结构。GPC测得聚磷腈的Mw=1.28×104。热分析结果显示聚磷腈的Tg=20℃,并在300℃开始分解。     

一种咔唑类衍生物的合成及其探针性能研究

用两步简便方法合成了基于咔唑基的荧光探针2,6-二(9-乙基咔唑-3氨甲基)-4-叔丁基苯酚,并对其光谱性能和离子选择性进行了研究.结果表明:在pH=7.4的体系中,该化合物对铜离子具有较强的选择性,铜离子的出现使得该探针在438nm处的荧光猝灭,且猝灭程度和铜离子浓度之间呈现良好的线性关系.     

Synthesis and Spectroscopic Study of Coumarin Derivatives

Five new coumarin amide derivatives were synthesized with coupling reagent,the structures of which were characterized by IR,1H NMR,13C NMR,MS and element analysis.Their spectral properties were studied in dichloromethane,in N,N-dimethylformamide(DMF) and in solid state.Solvent polarity has less influence on the UV-Vis maximum absorption at about 430 nm.The maximum emission wavelengths change from 464 nm to 474 nm in dichloromethane,from 476 nm to 482 nm in DMF and from 521 nm to 548 nm in solid state,respec...     

Spectroscopic Characterization of Carbazole-TCAQ Charge-Transfer Salt

Spectroscopic characterizations of carbazole-TCAQ salt were investigated by means of UV-visible and fluorescence spectra. The results show that carbazole and TCAQ can form a kind of charge-transfer salt whose characteristic adsorption is π→π^* of 248 nm when the mixture of the two compounds is irradiated by UV-light, and the charge-transfer salt becomes more stable with the increase of irradiation time.     

Fluorescence Spectroscopic Study for Interaction of Pyrene-Labeled Poly(2-acrylamido-2-methylpropane Sulfonates)s Bearing Octadecyl Group with Nonionic Surfactant Molecules

The interactions of the hydrophobically random-modified and end-capped polyanions with a nonionic surfactant were investigated by fluorescence spectroscopy of the labeled Py in the polyanions. The results revealed that the complex formation between these polyanions and the nonionic surfactant took place with two steps; the first step is the insertion of the surfactant molecules into hydrophobic microdomains formed from the polyanions, and the second step is the disruption of the hydrophobic microdomains due to binding the surfactant molecules to the hydrophobic groups of the polyanions. The position of the hydrophobic groups covalently introduced in the polyanions affects the polyanion-surfactant complex formation.     

薄膜三重价态锰氧化物的制备与性能

应用偏靶射频磁控溅射方法在SrTiO3(001)单晶衬底上制备了三重价态(Mn3+, Mn4+, Mn5+)锰氧化物薄膜La1-x-yCaxKyMnO3. 这种薄膜具有钙钛矿结构, A位拥有La3＋, Ca2＋和K＋三种离子, 对应的B位为Mn3＋, Mn4＋和Mn5＋三重价态离子共存. 通过18 kW高能X射线衍射仪和D8 X射线面探衍射仪检测证实制备的薄膜为取向多晶薄膜. 原子力扫描图像显示薄膜表面平整, 且随薄膜厚度增加表面平整度起伏增大. 表面光电压测试显示, 该薄膜具有明显的光生电压信号.     

Hydrothermal Syntheses and Characterizations of Three ZnII Coordination Polymers Tuned by pH Value and Base

Three new Zn^II coordination polymers, [Zn(bpe)(HL)₂(H₂O)]_n ( 1 ), {[Zn(bpe)(L)] · H₂O}_n ( 2 ), and [Zn₂Ca(bpe)(HL)₂(L)₂]_n ( 3 ) [H₂L = 5‐methoxyisophthalic acid and bpe = 1,2‐dis(4‐pyridyl) ethylene], were hydrothermally synthesized under different pH values and bases. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analyses and IR spectroscopy. Polymer 1 is formed at pH = 4 and has a 1D chain structure. These 1D chains are linked by hydrogen bonds to afford a 1D double chain and further to form a threefold interpenetrating network. At pH = 7, a 2D layer structure of 2 with sql topology is formed. By using calcium hydroxide as base for the synthesis of 3 , a 3D network with pcu topology is obtained. These structural differences among 1 – 3 indicate that pH value and the identity of the base play important role in defining the overall structures of metal‐organic frameworks. In addition, the fluorescent properties of 1 – 3 are discussed.     

A Spectroscopic Study of Charge Transfer Complexes of Tetraphenylporphyrin

Summary. The fluorescence quenching and complexation behaviour of tetraphenylporphyrin (TPP) with some organic acceptors such as chloranilic acid (CHL), 5,5-dithiobis-2-nitrobenzoic acid (DTNB), or 3,4-dinitrobenzoic acid (DNB) and tetravalent metal ions such as Th⁴⁺ and Zr⁴⁺ have been studied in methanol. The second-order fluorescence quenching rate constant (k_q), the association constant (K), the molar absorption coefficient (), and the thermodynamic parameters of the complexation process (G°, H°, and S°) have been evaluated using different organic solvents.     

光谱法研究哈巴俄苷与人血清白蛋白的结合反应

在不同温度及模拟血液pH值条件下,采用荧光光谱法和紫外-可见吸收光谱法研究了哈巴俄苷(Harpagoside, HAR)与人血清白蛋白(Human serum albumin, HSA)的结合反应.结果表明,HAR有规律地使HSA内源荧光猝灭,猝灭常数随温度升高而降低,其猝灭机制为两者形成复合物而引起的的静态猝灭;不同条件下两者结合常数KA均大于105 L/mol,结合位点数n≈1.由Van′t Hoff方程计算获得了不同条件下HAR与HSA相互作用的热力学参数,由ΔG、ΔH和ΔS均小于0可知,两者结合的主要作用力是氢键和范德华力,且两者结合是吉布斯自由能降低的自发过程.根据F(o)rster非辐射转移理论计,计算了不同条件下HAR与HSA的结合距离r在4.01~4.28 nm范围内,表明两者结合过程发生了非辐射能量转移.同步荧光光谱表征结果表明,HAR使HSA的色氨酸和酪氨酸残基所处的微环境极性增强,疏水性减弱,导致HSA构象发生了一定程度的改变.     

Structural and Infrared Spectroscopic Study on Solvation of Acetylene by Protonated Water Molecules

The effect of solvation on the conformation of acetylene has been studied by adding one water molecule at a time. Quantum chemical calculations of the H⁺(C₂H₂)(H₂O)_n (n=1-5) clusters indicate that the H₂O molecules prefer to form the OH…π interaction rather than the CH…O interaction. This solvation motif is different from that of neutral (C₂H₂)(H₂O)_n (n=1-4) clusters, in which the H₂O molecules prefer to form the CH…O and OH…C H-bonds. For the H⁺(C₂H₂)(H₂O)_n cationic clusters, the first solvation shell consists of one ring structure with two OH…π H-bonds and three water molecules, which is completed at n=4. Simulated infrared spectra reveal that vibrational frequencies of OH…π H-bonded O-H stretching afford a sensitive probe for exploring the solvation of acetylene by protonated water molecules. Infrared spectra of the H⁺(C₂H₂)(H₂O)_n(n=1-5) clusters could be readily measured by the infrared photodissociation technique and thus provide useful information for the understanding of solvation processes.