基于激发态分子内质子转移(ESIPT)原理的反应型荧光探针研究进展

基于激发态分子内质子转移(ESIPT)原理的反应型荧光探针,因其具有高选择性、高灵敏度及大的斯托克斯位移等优点而被广泛关注.以检测目标物的属性归类,就近十年ESIPT反应型荧光探针进行综述,阐述其检测识别机制,并对此类荧光探针应用中存在的问题及发展方向进行评述.     

苯胺类受体荧光探针识别位点的差异性构筑与识别机制研究

为实现分子水平上对小分子荧光探针与目标物结合过程的识别机制研究,分别以苯胺、邻苯二胺、间苯二胺作为起始原料,定向构筑荧光探针结构。构建柔性羧酸链作为探针对目标物的结合位点,分别引入了两个、邻位四个与间位四个识别位点,合成得到一系列结构相似、仅识别位点有差异性的苯胺类受体荧光探针TI、T4、T5。光谱性能分析结果显示;T...     

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。     

一种识别苯及Cu2+的多功能荧光探针的合成与性能研究

以三苯胺为电子给体,苯为共轭桥,二氨基马来腈为电子受体和识别基团,合成了一种席夫碱型多功能荧光探针TB-DAT。通过质谱、元素分析、¹H NMR、¹³C NMR等表征了其结构,利用紫外吸收光谱和荧光光谱对其光物理性能及对检测目标的特异性识别。结果显示,所合成的荧光探针该在苯溶剂中发出最大发射峰为530 nm的黄绿色荧光,从而在一系列苯系物中识别出有毒的苯。另外,该荧光探针还能够在乙腈溶液中通过明显的荧光增强行为实现铜离子的特异性识别,检测限低至0.73μM,且对其他金属离子有很好的抗干扰能力。     

一种新型一氧化氮比率型近红外荧光探针的制备及应用

该文以邻苯二胺修饰的［c］［1, 2, 5］噻二唑-5, 6-二胺作为一氧化氮（NO）识别基团和电子受体,芴衍生物作为荧光基团和电子供体,合成了一种新型检测NO的近红外荧光探针。通过紫外可见吸收光谱和荧光光谱研究探针分子的光谱学性质及检测NO的可行性。该探针与NO反应后生成苯并三氮唑结构,分子内电荷转移（ICT）效应加强,在近红外区的荧光明显增强。相较于传统的增强型或猝灭型NO荧光探针,该文制备的荧光探针通过比率计量荧光检测信号,实现了背景荧光低、抗干扰能力强的NO近红外荧光检测。该荧光探针受外界干扰小,且不与其他活性氧、活性氮反应,能够对不同浓度的NO产生快速、灵敏的荧光响应,对NO的检测线性范围为0～10 μmol/L,检出限为28.88 nmol/L。选择性实验表明,该探针对NO的响应具有专一性和抗干扰性。该文制备的比率型荧光探针能实现NO近红外荧光分析和检测,具有背景荧光低、抗干扰能力强的优点,可用于生物样品中NO的检测。     

智能型金纳米棒荧光探针的制备及其肿瘤细胞成像研究

开发能特异和灵敏检测基质金属蛋白酶-2(MMP-2)的智能型荧光分子探针,对于癌症的早期精准诊断与治疗至关重要。本文基于MMP-2特异性识别的多肽底物,利用一价铜离子催化的"点击"化学反应将荧光素(FITC)和多肽底物GPLGVRGY相偶联,与SH-PEG-COOH修饰的金纳米棒在EDC和Sulfo-NHS的作用下通过酰胺化反应,制备得到一种新的MMP-2特异性响应的荧光共振能量转移(FRET)金纳米棒探针GNR@FITC。体外重组酶检测实验、MTT实验及细胞共聚焦显微成像结果表明,该探针对MMP-2过表达小鼠乳腺癌细胞4T1表现出较好的特异性和检测灵敏度,具有进一步开发应用于乳腺癌早期诊断的极大潜力。     

基于激发态能量转移机理比率型荧光探针的研究进展

激发态能量转移(Excitation Energy Transfer,EET)作为一类重要的光物理现象,被广泛用于比率型荧光探针和分子灯标的设计以及DNA检测等多个领域.影响EET效率的两个重要因素是供受体间的空间距离和光谱交盖,通过调节供受体间的空间距离或光谱重叠程度来调控能量转移过程,实现对目标客体的双波长比率检测.综述了基于不同供受体荧光团的EET体系、供受体间的连接方式对能量转移效率的影响,以及通过调控供受体间光谱重叠程度或空间距离,获得识别不同客体的比率型荧光探针,并对EET机理的比率型荧光探针的设计以及未来在生物成像和医学检测等领域的应用进行了展望.     

基于链置换循环无标记检测端粒酶RNA的荧光法

以氧化石墨烯(GO)作为DNA载体和荧光猝灭剂, SYBR Green Ⅰ(SGⅠ)为荧光信号探针, 发夹核酸探针为分子识别探针, 基于目标物启动的发夹核酸探针链置换循环反应, 建立了一种利用荧光共振能量转移和链置换循环放大技术检测端粒酶RNA(hTR)的荧光新方法. 发夹核酸探针hpDNA1和hpDNA2吸附在GO表面, 嵌插在发夹DNA探针茎部的SGⅠ的荧光信号被GO猝灭. 当人工合成的目标物(T1)存在时, T1与hpDNA1杂交打开hpDNA1的茎-环结构而引发hpDNA2与T1之间的链置换循环反应, 由此累积产生大量的hpDNA1/hpDNA2杂交双链. 刚性的双链DNA脱离GO表面, 导致所嵌插的SGⅠ产生较强的荧光信号. 基于荧光信号的变化, 可定量检测0.2~50 nmol/L的T1, 检出限为90 pmol/L. 该方法为端粒酶RNA检测提供了一种高灵敏、 高特异性且无需标记的荧光新途径.     

罗丹明B衍生物的合成及其对Cu2+,Hg2+的识别研究

以罗丹明B-酰肼和2-羟基-3-喹啉醛缩合反应得到新型罗丹明B衍生物L,其结构经1H NMR,MS及元素分析表征.通过紫外光谱法和荧光光谱法研究了目标物L在CH3CN-H2O溶液中与金属离子的识别特性.结果表明:目标物L作为探针可选择性比色识别Cu2+和荧光识别Hg2+.随着Cu2+或Hg2+的滴加,探针L的内酰胺环结构发生开环,并形成L-Cu2+1∶1配合物或L-Hg2+1∶2配合物,识别过程均是可逆的.     

聚合物在荧光检测领域的应用

聚合物是由一种或几种重复单体以共价键连接形成的大分子化合物, 它不仅能够保持单体的性质, 而且由于聚合后单体间的协同作用, 使其表现出独特的性能. 聚合物作为基础材料在荧光检测领域得到广泛应用. 聚合物通过氢键作用、 亲疏水作用及范德华力等分子间相互作用, 实现了对特定目标物的选择性识别; 通过信号转换和放大功能, 可以将分子识别作用转化为荧光信号; 可以作为骨架连接多个识别单元, 通过多价结合作用等提高识别目标物的能力, 或连接不同的功能单元, 构建多功能的分子器件. 本文对聚合物在荧光检测领域的应用进行了概述.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.