纳米银对铕配合物荧光性质的影响(英文)

研究了纳米银对稀土铕-吡啶-2,6-二羧酸配合物(Eu(Ⅲ)C7H5NO4,Eu(Ⅲ)DPA)的荧光性质的影响。随着纳米银浓度增加,荧光强度先增强而后逐渐下降。较大粒径的纳米银使Eu(Ⅲ)DPA荧光增强效率较大,且达到最大荧光增强效率所需的纳米银浓度较低。在高浓度Eu(Ⅲ)DPA溶液体系中,纳米银导致荧光猝灭。电偶极子跃迁发射荧光增强效率大于磁偶极子跃迁发射荧光增强效率。分析认为,纳米银对Eu(Ⅲ)DPA荧光性质的影响与表面等离子体共振与激发态荧光中心强烈耦合以及表面等离子体再吸收有关。同时,纳米银对铕配合物的不对称率有影响,其影响因素与局域电磁场增强,折射率以及配位场有关。     

纳米银对铕-吡啶-2,6-二羧酸配合物荧光增强效应的研究

研究了纳米银对分别以水、重水、乙醇和二甲基甲酰胺为溶剂的铕-吡啶-2,6-二羧酸(Eu(Ⅲ)DPA)配合物溶液的荧光增强效应. 研究结果表明,Eu(Ⅲ)DPA溶液中加入纳米银,电偶极跃迁(⁵D₀→⁷F₂)和磁偶极跃迁(⁵D₀→⁷F₁)发射强度先增强而后逐渐下降,⁵D₀→⁷F₂的荧光增强效率高于⁵D₀→⁷F₁的荧光增强效率. 在乙醇溶剂中纳米银对Eu(Ⅲ)DPA溶液的荧光增强效应最大. 在水或重水或乙醇溶剂中,Eu(Ⅲ)DPA的不对称率明显提高,而在二甲基甲酰胺溶剂中几乎不变. 分析认为,纳米银对Eu(Ⅲ)DPA溶液荧光的影响与纳米银表面等离子体共振与激发态荧光中心强烈耦合以及表面等离子体再吸收有关.     

纳米银对铕-吡啶-2,6-二羧酸配合物荧光增强效应的研究

研究了纳米银对分别以水、重水、乙醇和二甲基甲酰胺为溶剂的铕-吡啶-2,6-二羧酸(Eu(III)DPA)配合物溶液的荧光增强效应.研究结果表明,Eu(III)DPA溶液中加入纳米银,电偶极跃迁(5D0→7F2)和磁偶极跃迁(5D0→7F1)发射强度先增强而后逐渐下降,5D0→7F2的荧光增强效率高于5D0→7F1的荧光增强效率.在乙醇溶剂中纳米银对Eu(III)DPA溶液的荧光增强效应最大.在水或重水或乙醇溶剂中,Eu(III)DPA的不对称率明显提高,而在二甲基甲酰胺溶剂中几乎不变.分析认为,纳米银对Eu(III)DPA溶液荧光的影响与纳米银表面等离子体共振与激发态荧光中心强烈耦合以及表面等离子体再吸收有关.     

噻吩甲酰三氟丙酮和4，5-二氮芴-9-酮及4，5-二氮芴-9-酮连氮铕(Ⅲ)三元配合物的合成和表征

合成了Eu(TTA)₃L1(Ⅰ)和［Eu(TTA)₃］₂L2(Ⅱ)二种新的铕(Ⅲ)三元配合物(TTA=噻吩甲酰三氟丙酮一价阴离子、L1=4,5-二氮芴-9-酮、L2=4,5-二氮芴-9-酮连氮)。用元素分析、IR、UV和溶液荧光光谱对配合物进行了表征。探讨了溶剂对Eu(Ⅲ)三元配合物荧光光谱的影响，发现在CH₃CN中Eu(Ⅲ)三元配合物发光效果最好，而溶剂DMF会使配合物荧光减弱。     

纳米Ag@SiO2核壳结构的表面等离子体共振效应对铕配合物的荧光增强作用

分别制备了二氧化硅壳层厚度为10、25和80 nm的三种Ag@SiO₂纳米粒子, 合成了铕与不同比例苯甲酸根(BA)的配合物、铕与1, 10-邻菲罗啉(phen)及2, 2''-联吡啶(bpy)的配合物, 并对其进行表征. 表征结果推测配合物的组成为Eu(BA)_nCl_3-n·2H₂O (n=1, 2, 3)、Eu(phen)Cl₃·2H₂O和Eu(bpy)Cl₃·2H₂O. 配合物的荧光光谱显示, 在加入Ag@SiO₂纳米粒子后, 复合物的荧光强度有不同程度的增加, 这可能是由于表面等离子体共振造成的. 不同硅壳厚度的Ag@SiO₂纳米粒子的荧光增强顺序是25 nm>80 nm>10 nm, 这表明二氧化硅核壳厚度约25 nm时有较强的表面等离子体共振效应. 此外, 在这些复合物中, Eu(phen)Cl₃·2H₂O复合物的增强效果是最强的, 而Eu(BA)_nCl_3-n·2H₂O的增强效果是最弱的. 在三个苯甲酸铕配合物中, Eu(BA)₃·2H₂O的增强效果最弱, 其他两个苯甲酸铕复合物增强效果相对较好. 原因可能是含氮配合物(Eu(phen)Cl₃·2H₂O和Eu(bpy)Cl₃·2H₂O)可以和Ag@SiO₂更好地成键, 而苯甲酸铕配合物和Ag@SiO₂纳米粒子的作用相对较弱. Ag@SiO₂纳米粒子有望应用于增强稀土材料的发光.     

一个手性吡啶甲酸铕(Ⅲ)配合物的合成、晶体结构和荧光性能

合成了1个以2-吡啶甲酸为配体的铕(Ⅲ)配合物[Eu(pic)₃]_n(1),通过红外光谱,元素分析,热重分析和X-射线单晶衍射对其进行了表征。配体2-吡啶甲酸通过其N,O螯合作用桥联了铕(Ⅲ)离子,形成了具有2₁右手螺旋结构的一维链状配合物1。荧光分析表明,配合物1的荧光光谱表现出铕(Ⅲ)的特征光致发光。     

一对手性铕（Ⅲ）配合物的合成和铁电性质

合成并表征了一对蒎烯修饰的稀土铕（Ⅲ）配合物Eu（TTA）₃L_1a（1a）和Eu（TTA）₃L_1b（1b）（TTA=2-噻吩甲酰三氟丙酮,L_1a=（+）-4,5-双蒎烯-2,2''-联吡啶,L_1b=（-）-4,5-双蒎烯-2,2''-联吡啶）。化合物的手性特征通过X射线单晶结构和圆二色光谱进行了表征。配合物1a结晶于极性空间群P1,中心Eu（Ⅲ）离子呈现出严重扭曲的四方反棱柱体的配位环境。鉴于非中心对称结构的特性,配合物1a也表现出明显的铁电性质。     

一对手性铕（Ⅲ）配合物的合成和铁电性质

合成并表征了一对蒎烯修饰的稀土铕（Ⅲ）配合物Eu（TTA）₃L_1a （1a）和Eu（TTA）₃L_1b （1b）（TTA=2-噻吩甲酰三氟丙酮,L_1a=（+）-4,5-双蒎烯-2,2''-联吡啶,L_1b=（-）-4,5-双蒎烯-2,2''-联吡啶）。化合物的手性特征通过X射线单晶结构和圆二色光谱进行了表征。配合物1a结晶于极性空间群P1,中心Eu（Ⅲ）离子呈现出严重扭曲的四方反棱柱体的配位环境。鉴于非中心对称结构的特性,配合物1a也表现出明显的铁电性质。     

基于两性离子配体构筑的Eu（Ⅲ）配位聚合物的晶体结构和对呋喃西林的检测

合成了一个新的铕（Ⅲ）配合聚合物{[Eu （L）₂（H₂O）₄]Cl₃·2H₂O}_n （1）（L=1,1''-（2,3,5,6-四甲基-1,4-亚苯基）双（亚甲基）双（吡啶-1-鎓-4-羧酸盐））。配位聚合物分子结构经X射线单晶衍射分析确认。对配合物1进行了X射线粉末衍射、红外光谱、热重法和固体荧光光谱表征。固体荧光测试显示配合物1具有非常明显的稀土铕离子特征发光,表明配体能够高效地敏化稀土离子发光。此外,这种水稳定的1被用作化学传感器来检测各种常见的抗生素,发现它对水相中的呋喃西林分子表现出高选择性、高灵敏度和可循环的检测能力。     

类Salen和β-二酮稀土配合物的晶体结构和荧光性质

通过配体1,3-苯二胺缩邻香兰素和Ln（acac）₃·H₂O（Ln=Ce,Eu）反应,合成了2个双核稀土配合物[Ce₂L（acac）₄（CH₃OH）]₂·2CH₃Cl₂（1）和[Eu₂L（acac）₄（CH₃OH）]₂·2CH₂Cl₂（2）。X射线单晶衍射分析确定了配合物的晶体结构,配合物中2个稀土离子均为8配位,具有相同的反四棱柱的配位构型。荧光性质研究表明配合物2显示稀土离子和配体共发光,主要原因是配体1,3-苯二胺缩邻香兰素的三线态能级与中心离子Eu（Ⅲ）的三线态能级相匹配。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。