3-巯基丙酸修饰的CdSe/ZnS量子点的合成及测定牛血清白蛋白的研究

以3-巯基丙酸作为修饰剂,在水溶液中合成了稳定的CdSe/ZnS量子点(QDs),透射电镜观察所合成量子点的形貌近似球形,粒径约为25 nm.吸收光谱与荧光光谱的研究表明,CdSe QDs在410 nm处有最大吸收峰,而CdSe/ZnS QDs的最大吸收峰在470 nm处,CdSe/ZnS QDs的荧光强度是CdSe QDs的11倍.考察了缓冲溶液的体积、pH值、反应温度、反应时间对体系荧光的影响.在最佳实验条件下,体系的荧光强度与BSA的浓度呈线性关系,线性响应范围为0.746×10-7～4.48×10-7 mol/L,检出限为3.846×10-10 mol/L.并且CdSe/ZnS QDs荧光强度基本保持稳定,可达两个多月.该方法应用于合成样品的测定,结果满意.     

镉(Ⅱ)-半胱氨酸配合物对CdS量子点的荧光增强作用及其在离子检测中的应用

合成了弱配体柠檬酸三钠修饰的CdS量子点(Cit-CdS QDs), 透射电子显微镜表征结果表明, Cit-CdS QDs的粒径分布均匀(4~6 nm), 分散性好。 研究了金属离子(银(Ⅰ)离子、镉(Ⅱ)离子)、巯基化合物(巯基乙酸、半胱氨酸)以及金属离子(银(Ⅰ)离子、镉(Ⅱ)离子)与巯基化合物形成的配合物对Cit-CdS QDs荧光的影响。 发现金属离子(银离子、镉离子)与巯基化合物(巯基乙酸、半胱氨酸)形成的水溶性配合物可以显著增强Cit-CdS QDs的荧光, 配合物对Cit-CdS QDs的增强程度比单独的金属离子或巯基化合物均要高, 而且配合物修饰的CdS QDs对铜(Ⅱ)离子的响应要高于单独用金属离子或巯基化合物修饰的量子点。 建立了铜(Ⅱ)离子高灵敏度荧光检测方法, 该方法检测范围宽(1.0×10^-8~1.0×10^-6 mol/L), 检测限低(1.0×10^-9 mol/L)且具有很好的选择性, 拓展了配合物作为量子点修饰剂的应用。     

3-巯基丙酸修饰的CdTe量子点荧光探针用于碘酸根离子的检测

以3-巯基丙酸(MPA)为稳定剂,采用水相合成法制备了CdTe量子点(QDs)。基于IO-3可使CdTe QDs荧光显著猝灭的特性,建立了一种检测IO-3的荧光分析新方法。优化了实验条件,在pH=6.0、三酸缓冲溶液浓度为30mmol/L、QDs溶液浓度为8.66×10-6 mol/L、反应时间为24min最佳实验条件下,检测IO-3的线性范围为6.0×10-8~7.2×10-6 mol/L,检出限为4.92×10-8 mol/L,方法相对标准偏差为2.37%。实验表明,IO-3对CdTe QDs的荧光猝灭有较好的选择性。方法用于自来水中IO-3的回收率实验,回收率为92.17%~103.29%。对可能的机理进行了探讨。     

基于L-半胱氨酸功能化的MoS_2荧光量子点检测Hg~(2+)

本文采用水热法,以Na_2MoO_4为钼源,L-半胱氨酸作为硫源及稳定剂,合成荧光二硫化钼量子点(MoS2QDs),利用紫外-可见光谱、荧光光谱和红外光谱对量子点的结构和性能进行了表征。所合成MoS2QDs呈现较强蓝色荧光的性能,并具有较好的分散性。MoS_2QDs作为探针与Hg~(2+)作用后产生荧光猝灭现象,由此建立了一种测定Hg~(2+)的荧光分析新方法。该方法对Hg~(2+)测定的线性范围是5.0×10-7~2.0×10-4 mol/L,检测限为2.3×10-7 mol/L,相关系数为0.998。该方法具有操作简单、灵敏度高和选择性好等特点,可用于自来水水样中痕量Hg~(2+)的测定。     

CdTe/CdS量子点与丝裂霉素的相互作用及其应用

在水相中合成了硫普罗宁(Tiopronin,TP)修饰的CdTe/CdS量子点(TP-CdTe/CdS QDs).利用紫外-可见吸收光谱、荧光光谱研究了TP-CdTe/CdS QDs与丝裂霉素(mitomycin C,MMC)的相互作用机理.在pH=7.6的tris-HCl缓冲溶液介质中,TP-CdTe/CdS QDs与MMC相互作用,使TP-CdTe/CdS QDs的荧光发生猝灭,并且QDs的荧光强度与MMC的浓度有良好的线性关系(r=0.9991),线性范围4.7×10-9～1.2×10-8g/mL,检出限(3σ)为1.4×10-g/mL.此方法快速简便,用于尿样中丝裂霉素的测定,实验结果令人满意.     

基于原位形成p-n结的新型光电化学传感器检测Hg~(2+)

利用简单方法合成了水溶性的巯基乙酸修饰的硫化镉(CdS)量子点。通过静电吸附,用聚二甲基二烯丙基氯化铵(PDDA)将CdS修饰到氧化铟锡(ITO)电极上。在电子供体三乙醇胺(TEA)的存在下,CdS修饰的ITO电极具有稳定的阳极光电流。Hg2+原位吸附于CdS表面形成的p型半导体HgS与n型半导体CdS形成p-n结,能够促进电子-空穴的分离与电荷传输,使CdS量子点的光电流增大。研究了反应前驱体中Cd,S摩尔比、反应溶液的pH值、回流时间等条件对所合成的量子点与Hg2+相互作用的影响。此外,还研究了电解质溶液的pH值、外加电压、反应时间对Hg2+增大CdS量子点光电流的影响。基于此,构建了灵敏检测Hg2+的光电化学传感器。该传感器对Hg2+响应的线性范围为4.0×10-8~2.0×10-5mol/L,检出限为2.4×10-8mol/L,回收率为98.3%~103.5%。     

栀子甙对碲化镉量子点的荧光淬灭作用

以3-巯基丙酸作为稳定剂,在水溶液中合成了CdTe量子点;采用荧光光谱法初步研究了栀子甙对巯基丙酸稳定的CdTe量子点的荧光淬灭作用,考察了量子点浓度、pH、反应时间等多种因素对量子点-栀子甙体系荧光强度的影响,确定了测定栀子甙的最佳实验条件;并初步探讨了栀子甙与该量子点相互作用的可能反应机理.结果表明,在最佳实验条件下,巯基丙酸稳定的CdTe量子点对栀子甙检测的线性范围为2×10-7~4×10-6 mol/L,检出限为1.4×10-7 mol/L,相对标准偏差为0.355%;且常见的金属阳离子、糖类和氨基酸对栀子甙的测定无显著影响.总体而言,该方法可用于人体体液中栀子甙的检测,且两者的作用过程可初步推断为动态淬灭过程.     

基于CdTe量子点的荧光猝灭-恢复法测定L-半胱氨酸

以巯基乙酸为稳定剂,合成了水溶性CdTe量子点(QDs),基于Ni~(2+)存在下,利用CdTe QDs荧光猝灭-恢复技术,建立了测定L-半胱氨酸的新方法。考察了缓冲溶液pH及Ni~(2+)浓度等对测定的影响。在pH=10.0的硼砂缓冲溶液中,Ni~(2+)浓度为40μmol/L条件下,L-半胱氨酸浓度在6.0×10~(-6)~5.0×10~(-5) mol/L范围内与量子点荧光恢复程度呈良好的线性关系,相关系数为0.9990,方法的检出限为2.1×10~(-6) mol/L。该方法应用于果汁和蜂蜜样品中L-半胱氨酸的检测,结果满意。     

水溶性量子点碲化镉测定同型半胱氨酸的研究

以巯基丙酸为稳定剂,在水溶液中一步合成了CdTe量子点,以该量子点为荧光探针,基于荧光增敏法对同型半胱氨酸(Hcy)进行选择性测定,考察了缓冲体系、缓冲液浓度、缓冲液pH值、反应时间、量子点浓度等多种因素的影响.在0.05 mol/L、pH 8.8的磷酸二氢钠-磷酸氢二钠缓冲液中,当量子点浓度为1.2 mmol/L、反应时间为10 min时,该方法的线性区间为0.1 ～60 μmol/L,检出限为8×10-8 mol/L.     

CdTe/CdS量子点荧光探针测定痕量锑

以巯基乙酸为稳定剂,在水溶液中合成了CdTe/CdS量子点(QDs),并基于QDs与锑混合后发生荧光猝灭作用,建立了以CdTe/CdS QDs作为荧光探针检测微量锑的新方法。研究表明,在pH值为4.80的柠檬酸-柠檬酸钠中,反应时间为10min时,锑浓度在0.03~2.50μg/mL范围与CdTe/CdS QDs的荧光猝灭程度呈良好的线性关系,相关系数为0.9969,检出限为2.60×10-3μg/mL。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.