8-羟基喹啉及其衍生物的锌配合物合成研究进展

简述了有机发光材料8-羟基喹啉金属螯合物的发展,综述了固相法和液相法合成8-羟基喹啉锌,例举了在喹啉环上的2、5和7号位引入供电子基团或大共轭基团的8-羟基喹啉衍生物的锌配合物性质,介绍了通过改变聚合度制备8-羟基喹啉衍生物的锌配合物方法,杂环和8-羟基喹啉共同做锌的配体合成新的发光材料的方法;最后对8-羟基喹啉和8-羟基喹啉衍生物的锌配合物的合成进行总结和展望。     

含三氟苯基8-羟基喹啉锌配合物的合成及紫外、荧光性能对比研究

设计合成了两种含三氟苯基的新型8-羟基喹啉衍生物配体:(E)-2-[2-(2,4,6-三氟苯基)乙烯基]-8-羟基喹啉(B)、(E)-5-[2-(2,4,6-三氟苯基)亚胺基]-8-羟基喹啉(C)及其相应的锌配合物D与E,产物经NMR,IR,MS,元素分析等进行结构表征。通过核磁、紫外滴定跟踪了金属锌与配体的配位过程,并测定了两者溶液状态下的荧光性质:化合物D,E在甲醇溶液中的荧光发射峰位置分别在599 nm和572 nm处;相比于8-羟基喹啉,2位和5位取代8-羟基喹啉衍生物的荧光发生了明显红移。锌配合物固体荧光寿命的测定结果表明,配合物D表现出较长的荧光寿命。     

金属卟啉荧光传感器对NH_3的识别研究

本文合成了一种基于金属卟啉和5-溴-8-氨基异喹啉的荧光配合物,并应用于一种识别NH_3的"开-关"荧光传感器,通过紫外可见光光谱观测了该传感器的形成动力学过程。NH_3迅速与传感器中心的钴或锌结合,同时5-溴-8-氨基异喹啉(ABIQ)从环中心离去,在激发光(λ_(Ex)=365nm)照射下发出蓝绿色荧光,实现对NH_3的检测。     

基于DPA识别基团的锌离子荧光传感器

锌离子在生物体系中扮演着重要角色,其分析和检测在疾病诊断和医疗检测等方面具有重要价值。用于 Zn²⁺ 检测的荧光传感器具有检测方便、灵敏度高等优点,引起了广泛关注。典型的荧光传感器通常是由识别基团和作为报告单元的荧光团通过间隔基团或直接连接而组成的。识别基团是荧光传感器的作用核心,在高选择性识别过程中起着至关重要的作用。自 1996 年第一次接在荧光素上以来,DPA (N,N-二(2-吡啶甲基)胺, di-2-picolylamine) 基团在锌离子传感器的设计中得到了广泛应用。本文综述了近年来文献中报道的基于 DPA 识别基团的锌离子传感器,介绍了锌离子荧光传感器的合成方法与识别原理,最后简单介绍了锌离子传感器中其它几种常见的识别基团。     

2-乙烯基硝基苯-8-羟基喹啉锌配合物的合成及紫外、荧光性质研究

设计合成了3种8-羟基喹啉衍生物配体:(E)-2-[2-(2-硝基苯基)乙烯基]-8-羟基喹啉(4a),(E)-2-[2-(3-硝基苯基)乙烯基]-8-羟基喹啉(4b),(E)-2-[2-(4-硝基苯基)乙烯基]-8-羟基喹啉(4c)及其相应的锌配合物5a～5c,产物经1H NMR,IR,MS和元素分析技术进行了结构表征.通过紫外滴定模拟了金属锌与配体的配位过程,分别测定了它们固态和溶液状态下的荧光性质:光谱显示化合物5a～5c固体荧光光谱的λmax分别是596,625,592 nm,在DMF溶液中的λmax分别是562,536,618 nm.荧光光谱显示硝基位置的改变可以调控8-羟基喹啉锌配合物的发光性质.     

8-羟基喹啉衍生物及其金属配合物的合成与光致发光特性

设计合成了三种新型的8-羟基喹啉衍生物配体: 5-[(4-E-苯乙烯基)-苯甲亚胺基]-8-羟基喹啉(1), 5-[(4-溴-2-氟)-苯甲亚胺基]-8-羟基喹啉(2)和N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑(3), 以及它们相应的金属配合物, 产物经质谱(MS)、元素分析(EA)、红外光谱(IR)、紫外光谱(UV)、核磁共振氢谱(¹H NMR)进行表征, 并测定了它们的荧光性质. 结果与8-羟基喹啉比较表明, 5位和2位取代8-羟基喹啉衍生物的荧光发生了明显的红移. 同时测定了配合物(3)₂Zn的荧光寿命, 结果表明, N-乙基-3-[2-(8-羟基喹啉基)-乙烯基]咔唑锌配合物表现出较长的荧光寿命.     

8-羟基喹啉席夫碱衍生物及其金属配合物的合成及荧光性质研究

设计合成了三种新的8-羟基喹啉席夫碱衍生物4-(8-羟基喹啉-5-亚胺甲基)-7-甲氧基苯并吡喃-2-酮(3a),4-(8-羟基喹啉-5-亚胺甲基)-7-己氧基苯并吡喃-2-酮(3b)和4-(8-羟基喹啉-5-亚胺甲基)-7-十八烷氧基苯并吡喃-2-酮(3c)及其铝、锌配合物,产物结构经1H(13C)NMR,MS,HRMS,IR和元素分析表征,研究了它们的荧光发光性能.     

二芳基大环冠醚共轭8-羟基喹啉的合成及光致发光性质

设计并合成了两种新型二芳基大环冠醚共轭8-羟基喹啉衍生物7a和7b及其锌配合物, 通过核磁共振(1H NMR, 13C NMR)、质谱(MS)、红外光谱(FT-IR)和紫外光谱(UV)等对7a和7b进行了结构表征. 初步研究了7a和7b及其锌配合物在溶液中的光致发光性质. 结果表明, 相对于2-甲基-8-羟基喹啉, 化合物7a和7b的荧光光谱向长波方向有明显的移动, 分别在460和467 nm处出现发射峰, 处于蓝光的范围. 配合物8a和8b的荧光发射峰分别为562和665 nm, 属黄光范围, 但荧光强度较弱.     

2-乙烯基氟代苯-8-羟基喹啉锌配合物的合成及光学性能研究

设计合成了2种新型的含不同氟原子数的8-羟基喹啉衍生物配体:(E)-2-[2-(2-氟代苯基)乙烯基]-8-羟基喹啉(4a)和(E)-2-[2-(五氟苯基)乙烯基]-8-羟基喹啉(4b)及其相应的锌配合物5a和5b,利用1H NMR、IR、MS、元素分析确认了产物结构。通过紫外滴定模拟了金属锌与配体4a和4b的配位过程,测定了其在二甲基甲酰胺(DMF)溶液中的荧光性质。荧光光谱显示:配体4a和4b在DMF溶液中的λmax分别为505 nm(蓝绿色)和517 nm(绿色),配合物5a和5b的λmax分别为559 nm(青绿色)和599 nm(黄色),配位后体系共轭程度增大,荧光光谱发生明显的红移。而且随着取代氟原子的增加,配体和配合物的荧光光谱也发生明显的红移。荧光光谱显示氟原子取代数量的改变可以调控8-羟基喹啉锌配合物的发光性质。     

四苯乙烯和三苯乙烯修饰的8-羟基喹啉聚集诱导发光特性研究

将2-甲基-8-羟基喹啉与四苯乙烯或三苯乙烯基团结合,合成了两种新型喹啉衍生物(4-Br-TPE-8HQ及TriPE-8HQ),并对其进行了光物理性能研究。结果发现,连接有四苯乙烯的喹啉衍生物能够体现聚集诱导发光(AIE)特性,而连接三苯乙烯的喹啉衍生物却显示温和的聚集诱导猝灭(ACQ)效应,实现了通过功能基团来调节目标分子聚集诱导效应的目的。研究发现,不同体系下分子的整体平面性有所不同,其中三苯乙烯修饰的衍生物在溶液中的荧光寿命(0.55 ns)高于固体荧光寿命(0.43 ns);循环伏安法证明两者具有良好的电化学稳定性,计算得到的4-Br-TPE-8HQ和TriPE-8HQ的LUMO能级分别为-2.40 eV和-2.43 eV,表明为两个化合物注入电子是可行的。     

镁离子荧光探针

镁离子（Mg²⁺）在许多生理过程中扮演着重要的角色,因此对镁离子的选择性识别引起了人们极大的关注。本文综述了近年来镁离子荧光探针的最新研究进展。镁离子荧光探针体系主要分为：喹啉类、β-二酮类、冠醚/多醚类、羧酸类、荧光素/罗丹明类、配合物类、聚合物类和纳米材料类等。本文列举了每类探针分子代表性的化合物并总结比较了不同类型的镁离子荧光探针体系。     

A quinoline-based selective ‘turn on’ chemosensor for zinc(II) via quad-core complex,and its application in live cell imaging

An efficient quinoline-based fluorescent chemosensor (QLNPY) was successfully developed for the detection of zinc ions (Zn²⁺). This novel chemosensor displayed higher sensitivity and selectivity toward Zn²⁺ over other competitive metal ions accompanying with obvious fluorescence enhancement. The QLNPY-Zn²⁺ complex can be further used as a new fluorescent “turn-off” sensor for pyrophosphate (PPi) and sulfur ion (S^2?) via a Zn²⁺ displacement approach. The limits of detection were calculated to be 3.8 × 10^?8 M for Zn²⁺, 3.7 × 10^?7 M for PPi and 4.9 × 10^?7 M for S^2?. The binding mechanism of QLNPY and Zn²⁺ was investigated through NMR, HR-MS analysis and further studied by crystallographic analysis. Additionally, further application of QLNPY for sequential bioimaging of Zn²⁺ and PPi was studied in HepG2 cells, suggesting that the quinoline-based chemosensor possesses great potential applications for the detection of intracellular Zn²⁺ and PPi in vivo.     

Modulating affinities of di-2-picolylamine (DPA)-substituted quinoline sensors for zinc ions by varying pendant ligands

We have developed a series of di-2-picolylamine (DPA)-substituted quinoline sensors, HQ1- 4, bearing a pendant ligand at the 8 position of quinoline. UV-vis spectra of HQ1- 4 showed similar variations to that of HQ5 but with different varying extents upon the titration of zinc ions. Fluorescence intensities of HQ1, HQ3, and HQ4 were enhanced 4-6 times upon the addition of 1 equiv of zinc ions under an aqueous buffer. Somewhat unexpectedly, HQ2 is nonfluorescent in the presence of metal ions, including zinc ions. The affinities of HQ sensors are distributed in a broad range from nanomolarity to femtomolarity by varying the pendant ligands near the coordination unit. More importantly, these new sensors exhibited very high selectivity for Zn(2+) over Na(+), K(+), Mg(2+), and Ca(2+) at the millimolar level and over other transition metal ions at the micromolar level, except for Cd(2+). These findings indicated that the incorporations of the pendant groups exerted no effect on the spectroscopic properties and selectivity of the parent fluorescent sensor, with the exception of HQ2. Finally, X-ray crystal structures of ZnHQ's revealed that the auxiliary pendant groups at the 8 position participated in zinc coordination and were able to tune the affinities of HQ sensors.     

The synthesis of luminescent lanthanide-based chemosensors for the detection of zinc ions

Herein, we report the synthesis of two lanthanide-based chemosensors, Tb-5 and Eu-6, designed to sense free zinc ions (Zn²⁺) in aqueous solutions. The Tb-5 complex features a bis(2-pyridinylmethyl)amine moiety as a zinc(II)-responsive lanthanide-sensitising ‘antenna’, while Eu-6 incorporates a quinoline-based moiety for this purpose. Luminescence enhancements of 210% and 340% are observed upon addition of Zn²⁺ ions to Tb-5 and Eu-6, respectively. Both sensors are selective for Zn²⁺ ions over several other cations of environmental significance.     

A fluorescent PEBBLE nanosensor for intracellular free zinc

The development and characterisation of a fluorescent optical PEBBLE (Probe Encapsulated By Biologically Localised Embedding) nanosensor for the detection of zinc is detailed. A ratiometric sensor has been fabricated that incorporates two fluorescent dyes; one is sensitive to zinc and the other acts as a reference. The sensing components are entrapped within a polymer matrix by a microemulsion polymerisation process that produces spherical sensors that are in the size region of 20 to 200 nm. Cellular measurements are made possible by the small sensor size and the biocompatibility of the matrix. The effects of reversibility, photobleaching and leaching have been examined, as well as the selectivity towards zinc over other cellular ions such as Na+, Ca2+, K+, and Mg2+. The dynamic range of these sensors was found to be 4 to 50 microM Zn2+ with a linear range from 15 to 40 microM. The response time for the PEBBLE is less than 4 s and the sensor is reversible. In addition, the nanosensors are photostable and leaching from the matrix, determined using a novel method, is minimal. These sensors are capable of real-time inter- and intra-cellular imaging and are insensitive to interference from proteins.     

Ultrasound-accelerated synthesis of quinoline-based luminescent imines exhibiting large Stokes shift

Russian Journal of General Chemistry - High yield synthesis of quinoline-based fluorescent imines, exhibiting the highest Stokes shift exceeding 380 nm (>18 000 cm–1), is reported in...     

Computational prediction and experimental evaluation of a photoinduced electron-transfer sensor

An approach is presented for the design of photoinduced electron-transfer-based sensors. The approach relies on the computational and theoretical prediction of electron-transfer kinetics based on Rehm-Weller and Marcus theories. The approach allows evaluation of the photophysical behavior of a prototype fluorescent probe/sensor prior to the synthesis of the molecule. As a proof of concept, a prototype sensor for divalent metal ions is evaluated computationally, synthesized, and then analyzed spectroscopically for its fluorescence response to zinc. Calculations predicted that the system would show a competition between electron transfer and fluorescence in the free state. In the zinc-bound state, the compound was predicted to be more highly fluorescent, due to the inhibition of electron transfer. Both predictions were confirmed experimentally. A nonzero fluorescence signal was observed in the absence of zinc and an enhancement was observed in the presence of zinc. Specifically, a 56-fold enhancement was observed over a 10-fold increase in zinc concentration.     

The zinspy family of fluorescent zinc sensors: syntheses and spectroscopic investigations

Four fluorescent sensors designed for Zn(II) detection that contain a fluorescein reporting group and a pyridyl-amine-thioether derivatized ligand moiety were prepared and their photophysical properties characterized. These "Zinspy" sensors are water soluble and generally display approximately 1.4- to approximately 4.5-fold fluorescence enhancement upon Zn(II) coordination, depending upon fluorescein halogenation and the number and nature of the zinc-binding appendages. The Zinspy sensors exhibit improved selectivity for zinc compared to the di-(2-picolyl)amine-based Zinpyr family.     

A Spin-orbit Coupling Study on the Quinoline-and Porphyrin-based Photosensitizers

The spin-orbit coupling(SOC) of four porphyrin- and quinoline-based compounds has been studied using Pauli-Breit SOC operator with one- and two-electron terms. The results revealed that the yield of singlet oxygen is affected by the spin-orbit coupling matrix element involving the emitting triplet and the perturbing singlet state. Investigated quinoline-based compounds have more high SOC values than those porphyrin-based compounds due to spin parallel electron pairs of oxygen. The open shell d8 of metal Pt can induce the stronger exchange interactions than the closed shell p6 of metal Mg, resulting in bigger SOC matrix element in quinoline-based Pt complex than in the quinoline-based Mg complex. Simultaneously, potential energy curves of the first excited sate and the first triplet sate have been calculated, which proves that all investigated complexes can induce singlet oxygen. These computational findings support quinolin-based compounds have high singlet oxygen yields and provide a rigorous basis for predicting the probability of singlet oxygen yields in plane-type molecules.     

Organelle-specific zinc detection using zinpyr-labeled fusion proteins in live cells

A protein labeling approach is employed for the localization of a zinc-responsive fluorescent probe in the mitochondria and in the Golgi apparatus of living cells. ZP1, a zinc sensor of the Zinpyr family, was functionalized with a benzylguanine moiety and thus converted into a substrate (ZP1BG) for the human DNA repair enzyme alkylguaninetransferase (AGT or SNAP-Tag). The labeling reaction of purified glutathione S-transferase tagged AGT with ZP1BG and the zinc response of the resulting protein-bound sensor were confirmed in vitro. The new detection system, which combines a protein labeling methodology with a zinc fluorescent sensor, was tested in live HeLa cells expressing AGT in specific locations. The enzyme was genetically fused to site-directing proteins that anchor the probe onto targeted organelles. Localization of the zinc sensors in the Golgi apparatus and in the mitochondria was demonstrated by fluorescence microscopy. The protein-bound fluorescence detection system is zinc-responsive in living cells.