DRS UV-Vis and EPR spectroscopy of hydroperoxo and superoxo complexes in titanium silicalite

The most important spectroscopic features in the UV-Vis of framework and extraframework Ti(IV) in titanium silicalite are briefly summarized. The spectroscopic manifestations of the complexes formed by framework Ti(IV) in presence of H₂O₂ are reported. The formation of EPR active species is also considered.     

合成1,4-苯撑-二-(5-氨基苯并噁唑)及电子光谱研究

以2，4—二氨基苯酚盐酸盐和对苯二甲酸为原料合成了1，4—苯撑—二—(5—氨基苯并噁唑)．反应过程中，首次加入还原剂SnCl2抑制2，4—二氨基苯酚盐酸盐的氧化，有效地提高了反应产率．通过熔点，元素分析，FT—IR，NMR，紫外—可见光谱表征化合物的结构．固体荧光光谱中，激发和发射光谱之间的Stokes位移说明固态分子间存在紧密的π堆垛，分子具有刚性的平面结构．可作为合成性能优异的芳杂环高聚物的单体原料．     

Photophysics of the porphyrins; unusual fluorescence of europium porphyrin complex entrapped in sol–gel silica matrix

In this paper, the study on encapsulation of water-soluble cationic porphyrins: methyl-pyridyl porphyrin (H₂TMePyP) and its Eu(III) complex in the monolith gels prepared by sol–gel method are reported. The samples doped with the porphyrins were prepared by tetraethoxysilane (TEOS) hydrolysis and condensation. Their absorption and emission spectroscopic properties in comparison with the spectra of the same compounds in various solvents are investigated. The spectra of metal complex were compared with those of free-base porphyrin. The strong fluorescence of europium porphyrin in the silica matrix is observed under excitation in Q-band (530 nm), while at the same time emission neither free-base porphyrin nor europium chloride does not occur. It can be explained by the strong interaction of the Eu(III)TMePyP(acac) with the silica.     

C-TiO2复合催化剂的制备及其表征

以大孔-介孔炭材料为催化剂载体,用溶胶-凝胶法合成制备复合光催化剂C-TiO2,并分别用X射线衍射(XRD)、透射电子显微镜(TEM)、UV-Vis漫反射光谱(DRS)对其物性进行表征;采用该复合催化剂降解甲基橙溶液评价其光催化效果.结果表明:C-TiO2复合材料不是简单的物理负载,而是在合成制备及高温煅烧后,在载体与催化剂的界面处发生了化学键合;与P25-TiO2相比,该复合催化剂催化效果显著提高.     

氨基酸-银反应的光化学特点

氨基酸与银的反应是一个不借外加能量热力学上即可进行的过程,但当引入光之后,可改变反应速率.研究发现:Soret带出现吸收所需光照度的大小顺序为Asp Ag(I)>Thr Ag(I)>Tyr Ag(I)>Lys Ag(I),对于Cys Ag(I)体系,Cys的α羧基氧、α氨基的氮与银(I)结合时光照有利于反应的进行,而S原子与银(I)结合与光照度几无关系.此反应是光助化学反应.     

Green synthesis of silver nanoparticles using Cyathea nilgirensis Holttum and their cytotoxic and phytotoxic potentials

The present study aimed at synthesizing silver nanoparticles (AgNPs) from the aqueous extract of C. nilgirensis and their biopotential using cytotoxicity and phytotoxicity. On mixing the aqueous extract with 1?mM AgNO₃ solution, the color changes from pale yellow to yellowish brown color. The absorption spectra of yellowish brown nanoparticle showed a plasmon absorption band with a maximum of 3.806 and 1.028 abs in 311 and 440?nm, respectively. The Fourier transform infrared spectroscopy (FTIR) spectra confirmed that phenolic compounds have stronger ability to bind with metal, indicating that phenolics could possibly form metal nanoparticles to prevent agglomeration and thereby stabilize the medium. The size of AgNP is found to be in the 45.0–74.0?nm range. The Energy-dispersive X-ray (EDX) spectra analysis revealed the presence of a strong Ag peak. The results indicated that C. nilgirensis aqueous extract was found efficient for the synthesis of AgNPs.     

UV—Vis光谱法与FT—IR光谱法研究聚苯乙烯老化

用紫外-可见光谱法与付里叶变换红外光谱法研究聚苯乙烯以及苯乙烯-丙烯酸酯共聚物的老化过程。在光、热、氧的作用下,这些聚合物的部分主链与侧苯基断裂,有少量苯乙酮结构生成,导致材料变色。     

混合染料的相互作用机理研究

利用模拟混合染料废水,分析了阳离子蓝FGL与酸性、活性、直接、阳离子、分散5种染料混合后的颜色变化机理和染料之间的作用。结果表明:阳离子蓝FGL基本上能与含磺酸基的酸性、活性和直接染料按电荷摩尔比发生作用,与同类的染料不会发生反应,与分散橙SE-B也会通过库仑力发生反应。混合液的色度在有沉淀生成时会变小,这样将节约废水处理的成本。     

主成分分析联合Fisher判别在紫外-可见光谱法水质检测中的应用

水质类型的判别是实现光谱法水质参数准确检测的重要前提。针对直接光谱法水质检测系统采集的光谱数据信息冗余较大的问题, 利用主成分分析消除信息指标间的相关性,实现光谱数据的降维和特征信息提取。采集某化工厂和某溪水水样的紫外-可见光谱数据, 利用主成分分析联合Fisher判别的方法建立判别模型,以12组水样光谱数据作为训练样本,6组作为测试样本,对模型的判别能力进行论证和检验,并与传统的Fisher判别模型进行对比实验。实验结果表明,利用主成分分析联合Fisher判别模型可以有效消除信息冗余带来的影响,相比传统的Fisher判别模型具有分类精度高、回代误判率为零、计算时间短等优点,计算时间由传统Fisher判别方法的0.6733 s减少到0.6012 s。该方法为直接光谱法水质类型判别工程实用化提供了一种高效手段。     

聚苯胺的合成及其光谱特性

:采用化学氧化聚合法 ,以苯胺为单体 ,过硫酸铵 (APS)为氧化剂 ,在酸性介质中合成聚苯胺(PAn) ,聚合物的比浓粘度 (ηSP) C=0 .1=1 d L/ g,酸掺杂后电导率 (σ)为 1 0 0 S/ cm。讨论了单体与氧化剂的比例、反应体系的温度以及聚合反应的时间对聚合产物的影响。采用傅里叶红外光谱 (FTIR)和紫外可见光光谱 (UV- Vis)对聚苯胺掺杂前后结构的变化 ,表明聚苯胺主链结构经质子酸掺杂后由于电子的离域形成了共轭结构 ,从而使聚苯胺有良好的导电性能。