基于T-Hg(Ⅱ)-T结合力和G-四联体非标记型汞离子传感器的研制

利用T-Hg(Ⅱ)-T特异性结合作用识别汞离子(Hg~(2+)),以G-四联体/卟啉类化合物NMM(N-甲基卟啉二丙酸IX)复合结构(G-四联体/NM M)作为荧光信号分子,开发了一种新型汞离子传感器。该传感器操作简单、经济实用且不需要人工修饰化学基团,而且由于G-四联体/NMM的最大发射波长为615 nm,有效避免了生物自发荧光的干扰。研究表明,在对钾离子浓度、NMM浓度等反应条件进行优化后,该传感器对汞离子的检测具有较高的选择性和灵敏性,检出限低至20 nmol/L,与世界卫生组织(WHO)所规定的饮用水中30 nmol/L汞离子标准相当,具有用于检测饮用水中汞离子的潜在实用价值。     

具有荧光增强性能的罗丹明B衍生物的合成及其对汞离子的检测

利用汞离子可以诱导罗丹明B衍生物的螺环结构发生开环反应并产生荧光增强效果这一特性,设计并合成了两种新型的荧光化学传感器2-噻吩甲醛罗丹明B酰肼(RhBTh)和苯甲醛罗丹明B酰肼(RhBAr),并研究了二者在汞离子检测中的应用.研究结果表明,RhBTh与RhBAr对汞离子均表现出非常好的荧光增强效果,检测过程中其它金属离子不会对检测结果产生明显的干扰.二者对汞离子的检测限分别为7.8 nmol/L和12.5 nmol/L.实验表明RhBTh和RhBAr对汞离子均具有良好的灵敏度和选择性.     

异硫氰酸荧光素功能化金纳米荧光法检测硫普罗宁

通过自组装方式获得了异硫氰酸荧光素修饰的金纳米,硫普罗宁上的巯基能够与异硫氰酸荧光素竞争性争夺金纳米表面,导致部分异硫氰酸荧光素远离金纳米,绿色荧光恢复,基于此构建了可用于高灵敏检测硫普罗宁的荧光传感器。汞离子的干扰可以通过EDTA进行掩蔽,有效消除干扰。传感器对硫普罗宁的线性检测范围为1. 0～750 nmol/L和1. 0～10. 0μmol/L,检出限为0. 85 nmol/L。     

基于纳米石墨和单链脱氧核糖核酸混合物的荧光传感器对溶液中汞离子的检测

利用纳米石墨、单链脱氧核糖核酸开发了一个新型的荧光生物传感器并使用脱氧核糖核酸酶作为信号放大器对溶液中的汞离子进行检测。在最佳实验条件下,这种新型荧光生物传感器对汞离子的检出限达到0.5 nmol/L,比传统未经信号放大的传感器低20倍。得益于汞离子(Hg~(2+))可以结合两个胸腺嘧啶碱基(T)形成强力且稳定的T-Hg~(2+)-T复合结构(T-Hg~(2+)-T)的作用,该传感器对汞离子有着出色的选择性。此新型荧光生物传感器有望成为未来检测其他金属离子和生物分子的新工具。     

含芘环的缩氨基硫脲类化合物的合成及其对汞离子的识别

合成了芘甲醛-4-甲基缩氨基硫脲(1)、芘甲醛-4-(4-乙苯基)缩氨基硫脲(2)、芘甲醛-4,4-二甲基缩氨基硫脲(3)三个化合物,并通过质谱、元素分析、傅立叶红外光谱和核磁共振氢谱进行了结构表征.利用荧光激发和发射光谱,对其荧光活性进行研究,并考察了对溶液中汞离子的识别作用.在分别向三种化合物的溶液中逐步滴加汞离子时,其特征的荧光发射波长处对应的强度值都呈现规律性变化.因此可利用比率荧光法实现对汞离子配合过程的观测.结果表明,三种化合物都能与汞离子形成1:1的配合物,配合常数分别为4.57×104,5.54×104和2.12×104L/mol,其检测下限分别为4.56×10-6,2.61×10-6和5.49×10-6mol/L.     

汞离子荧光、比色传感器

基于主客体识别的汞离子比色、荧光传感器由于使用方法简单、灵敏度高、不需要昂贵仪器等优势,受到了越来越多的关注。本文综述了近年来汞离子比色和荧光传感器的研究进展。本文根据作用机理将汞离子比色、荧光传感器分成三类,即通过特殊反应识别汞离子的传感器,通过配位作用识别汞离子的传感器以及基于纳米材料的汞离子传感器。其中通过特殊反应识别的传感器根据具体反应类型又可分成汞离子诱导的罗丹明上的内酰胺环开环型、汞离子与含硫(硒)的受体发生脱硫(硒)反应使受体氧化或关环型、汞离子与受体发生加汞化反应型和汞离子使受体发生汞离子催化的化学反应型这四类。本文对这些类型的汞离子传感器从设计原理、识别性能和机理等方面进行了介绍,并展望了该领域的研究方向。     

一种用于水样检测的快速汞离子荧光传感器

在440 nm激发波长下,核黄素水溶液在525 nm处能够产生荧光,汞离子(Hg2+)存在时其荧光被猝灭,基于此开发了一种用于水样中Hg2+浓度快速检测的荧光传感器。该传感器对Hg2+的检测线性范围是50 nmol/L～50μmol/L,检出限是8.0 nmol/L,响应迅速(约1 min),对其他金属离子具有很好的选择性,将其应用于湖水中Hg2+检测结果满意。     

基于T-Hg2+-T及G四聚体自身熄灭能力的“Turnon”型单标记DNA荧光探针用于碘离子的检测

利用G四聚体可以熄灭荧光的特性以及T-Hg2+-T的特殊结构, 发展了一种简便的"Turn on"型碘离子检测新方法. 设计了一条5'端标有荧光基团的富T序列, 3'端采用能形成G四聚体的富G序列代替传统的熄灭基团. 加入汞离子后, 富T序列形成T-Hg2+-T机构发生折叠, G四聚体靠近荧光基团, 发生光诱导电子转移, 使荧光被熄灭. 若加入碘离子, 碘离子会与汞离子形成较稳定的配合物, 汞离子从DNA上被竞争下来, 探针的荧光得以恢复, 且荧光强度与50～500 nmol/L的碘离子呈良好线性关系, 检出限为30 nmol/L. 本方法选择性好, 10倍于碘离子浓度的其它常见阴离子干扰较小. 检测自来水样中碘离子的回收率为92%～109%, 相对标准偏差RSD<4%(n=4).     

基于铜纳米线放大的汞离子高灵敏比色检测法

将滚环扩增技术与铜纳米线相结合进行信号放大,建立高选择性、高灵敏的汞离子比色检测新方法。以链霉亲和素修饰的磁珠为探针捕获和分离基质,将生物素修饰的引物链固定到其表面。汞离子存在时,模板链将通过T-Hg^2+-T作用与引物链结合。加入T4连接酶及DNA聚合酶引发滚环扩增反应形成超长单链DNA。与短单链DNA互补形成的长双链DNA可作为铜纳米线沉积模板,加入盐酸释放出大量铜离子催化底物氧化显色。在0.005~1.0 nmol/L范围,汞离子浓度与吸收信号呈良好线性关系,检出限低至3.7 pmol/L。     

对羟基苯甲醛缩邻氨基苯甲酸与汞的荧光猝灭反应及其应用

合成了一种新的席夫碱荧光试剂--对羟基苯甲醛缩邻氨基苯甲酸(HBAA).研究了HBAA与汞离子的络合反应及其反应条件,HBAA在390.0 nm处有一强荧光峰,汞离子存在时,可与其形成稳定的络合物并使HBAA的荧光猝灭.利用该反应建立了荧光测定痕量汞的新方法,方法的线性范围为0 ～90.0 μg/L,检出限为0.61 μg/L.考察了40种常见共存离子的干扰影响,结果表明合成的HBAA试剂具有很高的选择性.该方法简便、快速,可用于矿泉水、自来水、河水中痕量汞的测定.     

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.