硒杂环化合物(4,5-苯并苤硒脑)在金表面上的自组装

为了寻求新的自组装单分子膜体系,构建新的功能膜,研究了具备平面型的大环共轭硒杂环化合物-- 4,5-苯并苤硒脑(苯并[c]硒二唑,简称苤硒脑)在金表面的自组装单分子膜.通过X射线光电子能谱(XPS)和电化学手段对其进行表征.XPS研究结果表明,自组装形成单分子膜后,苤硒脑分子中Se3d结合能从57.4 eV下降到57.1 eV;表明硒杂环化合物是通过金硒键固定在金表面上的;电化学循环伏安法实验表明,金电极表面上自组装该有机硒后, Fe(CN)63-/4-的氧化还原峰几乎完全消失;以四硼酸钠为底液,测得该化合物自组装在金表面上时,其还原电位在-0.66 V,与在溶液中用裸金电极测得的还原峰电位基本一致.     

二溴代苤硒脑极谱吸附波的研究及应用

硒(Ⅳ)与邻芳香二胺类试剂能生成相应的苤硒脑衍生物,利用其电还原性质可用极谱法测定硒^[1,2],二溴代苤硒脑的极谱特性及应用尚未见报道.     

硒杂环化合物及其自组装膜的电化学性质研究

硒与芳香邻二胺类化合物反应定量、快速,且产物苤硒脑易于用光谱和电化学检测,在分析化学上具有重要地位[1 4],本文报道该类型化合物及其在金电极上的自组装膜的电化学特性。苤硒脑结构式如下:1　实验部分1 1试剂与仪器2,3 二氨基萘(2,3 diaminonaphthalene,DAN,Sigma公司),1,2 二氨基蒽醌(1,2 diamino qthraquinone,DAAQ,Aldrich公司),Na2SeO3及其余试剂均为A.R.级,丙酮经重蒸提纯,石英亚沸蒸馏器制高纯水,BAS-100B型电化学分析仪(美国)。1 2　实验方法苤硒脑按文献[4]法制备。DAN和DAAQ分别与Na2SeO3在暗室中反应制取BP和…     

用超声波加快硒-邻苯二胺的络合与萃取测定硒(Ⅳ)

邻苯二胺是常用的测定硒的络合剂,Ariyoshi等人曾以邻苯二胺为络合剂用紫外光谱法测定微量硒,侯家麟等用相同的方法测定了亚硒酸钠片中硒的含量,其原理是:邻苯二胺与亚硒酸发生络合反应生成3,4-苯并-1,2,5-重氮苤硒脑,再以甲苯萃取,用光度法测定萃取液。我们试用超声波作用使络合和萃取一步完成,该方法尚未见文献报道。     

紫外分光光度法测定硒氧化过程中二氧化硒

利用5-硝基-2,1,3-苯并苤硒脑对紫外光的吸收特性,用紫外分光光度计测定硒氧化过程中硒(Ⅳ)含量。研究了硒(Ⅳ)与4-硝基邻苯二胺(NPDA)生成5-硝基-2,1,3-苯并苤硒脑的衍生反应条件,验证了测定结果的准确性。结果表明:衍生反应适宜条件为pH2,反应温度60℃,反应时间10 min,NPDA试剂用量为硒(Ⅳ)的168倍。在0.002~0.02 g/L硒(Ⅳ)范围内,硒(Ⅳ)浓度与衍生产物5-硝基-2,1,3-苯并苤硒脑的吸光度线性关系良好。用该法测定硒氧化过程中二氧化硒含量,RSD为0.52%。硒(Ⅳ)的平均加标回收率为98.12%。本文建立的紫外分光光度法为硒含量较大的体系中硒(Ⅳ)定量分析提供了准确、便捷的测定方法,对于其它价态硒(Ⅵ价、Ⅱ价、0价)测定有借鉴作用。     

有机硒化合物的^7^7Se NMR研究

本文测定了一系列二茂铁有机硒衍生物及几种烷基硒醚、芳基硒醚化合物的^7^7Se NMR谱。确定了这些化合物的^7^7Se NMR化学位移值。着重讨论了影响^7^7Se化学位移的因素。与硒直接相连取代基的链长、支链化程度以及吸电子能力的改变对^7^7Se NMR化学位移有着不同程度的影响。除此之外, 溶剂效应对二茂铁有机硒类化合物的^7^7Se NMR化学位移也有一定程度的影响。     

在β-环糊精-十二烷基硫酸钠水溶液中荧光光度法测定痕量硒

本文提出,适当配比的β-环糊精(β-CD)和十二烷基硫酸钠(SDS),对4,5-苯并苤硒脑(记作Se-DAN)有协同增敏作用,可以不经环己烷萃取的步骤,在水溶液中直接荧光测定痕量硒。     

吸附溶出伏安法测定痕量硒——铜离子对二溴代苤硒脑体系的增敏作用

本文发现Cu~(2+)离子对二溴代苤硒脑在悬汞电极上的吸附溶出行为有显著增敏作用,从而建立了灵敏度高、选择性好的测定痕量硒的吸附溶出伏安法。线性范围为0.02～50ng/ml,检出下限达5×10~(-4)ng/ml。本文初步探讨了Cu~(2+)的增敏机制。     

分子荧光光谱法测定富硒大米中的痕量硒

硒(Ⅳ)与DAN(2,3-二氨基萘)生成具有荧光特性的4,5-苯并苤硒脑,可用分子荧光光谱法测定,优化测定的实验条件,建立了快速准确测定大米中痕量硒的方法.结果表明,其最佳测定条件为:pH=2.0,反应温度为80℃,1.0×10-5 mol/L十六烷基溴化吡啶用作表面活性剂,环己烷萃取条件下,增敏效果明显,在0～0.0...     

高效液相色谱／荧光检测法测定东北虎样品中的微量元素硒

１引言东北虎属猫科、豹属、虎种、东北虎亚种，具有较高的经济价值和观赏价值，是我国一类保护动物。野生东北虎所存的数量极其有限，已达到了濒临灭绝的境地。为了挽救这一濒危物种，我国有关科研人员在东北虎的人工饲养、繁育等方面做了大量有益的工作，但在对东北虎生理指标及与疾病有关的微量元素的研究上尚属空白。硒的测定方法有很多，其中高效液相色谱法以其灵敏度高、选择性好、分辨率高、操作简便等特点而广泛应用。本文根据２，３－二氨基萘（ＤＡＮ）与硒（Ⅳ）生成４，５－苯并苤硒脑（ＮＳＤ）络合物，用环己烷萃取，采用高效…     

新型染料敏化体系──荧光素染料碘鎓盐的光谱研究

本文合成了一系列荧光素类染料碘盐,并研究了其光谱及光化学性质。结果表明,通过改变结构,可改变它们的吸收光谱。提出可用I_Ⅰ/I_Ⅱ值来表征这类化合物在溶剂中的相对解离程度。随溶剂极性,染料母核C-6位周围(C-7,C-8位)空间位阻增大和染料母核上吸电子取代基增多,I_Ⅰ/I_Ⅱ值增大,它们的相对解离程度升高,光谱性质显着变化,光化学反应速度下降。在极性和非极性溶剂中,浓度对光谱和光化学性质具有不同的影响。显示这类化合物除可用作可见光敏化聚合和交联的光引发体系外,还可能用作探针探测周围环境的变化。     

Experimental and quantum-chemical studies of the 3-pyridine-7-hydroxy-2-iminocoumarin and 3-(2-methylthiazole)-7-hydroxy-2-iminocoumarin molecules

The luminescence spectral properties of 3-pyridyl-7-hydroxy-2-iminocoumarin and 3-(2-methylthiazole)-7-hydroxy-2-iminocoumarin were studied in ethanol solutions at different values of pH and also in other solvents differing in polarity. In their ethanol solutions, the compounds can exist as neutral molecules, anions, cations, and zwitterions. The spectral properties and geometry were studied for all possible forms of these compounds by the INDO/S quantum-chemical method.     

Electronic Absorption Spectra of Substituted Phenols

The spectral properties of o-aminophenol, catechol, o-nitrophenol, pyrogallol, salicylic acid and gallic acid were investigated in different solvents. The behaviour of hydrogen bonding demonstrated in these systems was discussed.     

Studies on a novel class of triaryl pyridine N-glycosylamine amphiphiles as super gelators

A novel class of six different triaryl pyridine N-glycosylamine amphiphiles was synthesised and characterized based on different spectral techniques, such as NMR and mass analysis. Gelation properties in different aromatic and aliphatic solvents were studied and gelation was observed predominantly in aliphatic solvents with CGC of 0.5% (w/v) and is attributed to the presence of long alkyl chain. All the gels thus obtained were studied using FE-SEM and powder XRD techniques which reveal fibrous entanglement of the molecules in the gel state with intermolecular spaces of 3.62 nm and 0.43 nm.     

香豆素衍生物溶液的光谱和光物理行为

通过对一系列不同取代的香豆素化合物在不同溶剂中的光谱测定,研究了结构和溶剂极性对它们光物理行为的影响.发现了它们的光物理特征与其结构和多种溶剂极性参数间存在的一些关系,为进一步更好的利用这类化合物提供了重要依据.     

Solvatochromic behaviours and structure–spectra relationships of 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes

Comprehensive electronic absorption spectra of a new dye series, 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes have been investigated in solvents of varying polarities. The solvent dependent UV–vis spectral shifts were analysed using some solvent physical parameters such as refractive index, dielectric function, hydrogen bonding acceptor ability, orientation of polarization and others. The observed spectral shifts were correlated with different solute–solvent interaction mechanisms using simple and multiple linear regression analyses. The results of the curve fitting coefficients enabled us to classify the various interactions of solvents with the dyes and relate the solvatochromic behaviours to the substituent effects on the dye molecules. Charge-transfer complexation occurring between one of the congeners and N,N′-dimethylformamide was extensively studied and discovered to be both concentration- and temperature-dependent.The electronic character and the chemical nature of the solvents as well as the chemical nature of the other substituents, apart from the common hydroxyl group, are important factors for the observed solvatochromic properties of the 4-carboxyl-2, 6-dinitrophenylazohydroxynaphthalenes.     

Solvent effects on the spectroscopic properties of 4-hexylresorcinol

A study was made on the spectroscopic properties of 4-hexylresorcinol (4HR) in several solvents at room temperature. Absorption and emission spectra were slightly affected by solvent polarity. Stokes' shifts were small (approximately 3000 cm(-1)) and the fluorescence quantum yields varied between 0.05 and 0.68, depending on the solvent. The spectral shifts were correlated with different solvent scales. Multiple regression analysis indicates that both non-specific solute-solvent interactions as well as specific solute-solvent interactions (such as hydrogen bonding) play an important role in the position of the Stokes' shift and on the fluorescence quantum yield in the solvents under study.     

Solvent polarity induced structural changes in 2,6-diamino-9,10-anthraquinone dye

Photophysical properties of 2,6-diamino-9,10-anthraquinone (2,6-DAAQ) dye have been investigated in different solvents and solvent mixtures. The fluorescence quantum yields, fluorescence lifetimes, radiative rate constants, nonradiative rate constants and absorption and fluorescence spectral characteristics show unusual deviations in the lower polarity aprotic solvents in comparison to those in other aprotic solvents of medium to higher polarities. The results indicate that the dye exists in different structural forms in the lower and in the medium to higher polarity solvents. Drawing an analogy with the results reported for other amino-substituted dyes, it is inferred that 2,6-DAAQ dye adopts a planar intramolecular charge transfer (ICT) structure in medium to higher polarity solvents, where the amino lone pairs are in good resonance with the anthraquinone pi-cloud. In the lower polarity solvents, however, the dye is inferred to exist in a nonplanar structure where the amino lone pairs are not in good resonance with the anthraquinone pi-cloud. Due to these structural differences, the dye displays significantly different photophysical behavior in the lower polarity solvents than in the other solvents of medium to higher polarities. Supportive evidence for the above structural changes has been obtained from ab initio quantum chemical calculations on the structures of the dye under different conditions. Unusual deviations in the photophysical properties of 2,6-DAAQ dye in protic solvents in comparison to those in aprotic solvents of similar polarities are attributed to the intermolecular hydrogen bonding effect involving the OH groups of the protic solvents and the quinonoid oxygens of the dye.     

光敏功能性表面活性剂及其稳态光谱性质

本文设计、合成了一系列新型的三重态光敏功能性表面活性剂——对苯甲酰苄基三烷基溴化铵(简称PKT)。测定了它们的吸收光谱和发光光谱,比较了它们分子聚集形成胶束前后的光谱性质,结果表明,在均相溶液中光敏基团保持原有光敏剂分子的光谱性质。但在水溶液中,在形成胶束临界浓度前后,BP基团的光谱性质发生突变,峰值发生红移并强度减弱。在非水溶液中,由于功能性表面活性剂是逐步缔合过程,光谱性质发生逐步变化。