基于2-(2′-吡啶基)苯并咪唑的Zn2+比例计量型荧光识别

本文以荧光分子2-(2'-吡啶基)苯并咪唑(2-PBI)作为1,1'-联(2-芳杂环)类化合物模型.研究利用其2,2'-N原子螯合Zn2 导芳环共面化和荧光发射红移实现Zn2 比例计量检测的可行性.2-PBI在不同体系中的Zn2 荧光响应行为表明Zn2 结合将导致最大发射波长明显红移(乙腈36 nm;HEPES缓冲液39 nm).具有比例计量型Zn2 荧光探针的基本特点.2-PBI还具有显著的Zn2 荧光响应选择性,可以同时作为构建比例计量型探针的信号团和受体的基本骨架.通过对2-BPI的荧光机制和Zn2 识别行为的分析,提出了以2-PBI为基本骨架构建实用化比例计量型探针的途径.     

基于2-（2’-吡啶基）苯并咪唑的Znn比例计量型荧光识别

本文以荧光分子2-（2’-吡啶基）苯并咪唑（2．PBI）作为1,1’-联（2-芳杂环）类化合物模型,研究利用其2,2＇-N原子螫合Zn2＋诱导芳环共面化和荧光发射红移实现Zn：＋比例计量检测的可行性。2-PBI在不同体系中的Zn2＋荧光响应行为表明Zn2＋结合将导致最大发射波长明显红移（乙腈36nm;HEPES缓冲液39nm）,具有比例计量型Zn2＋荧光探针的基本特点。2-PBI还具有显著的Zn2＋荧光响应选择性,可以同时作为构建比例计量型探针的信号团和受体的基本骨架。通过对2-BPI的荧光机制和Zn2＋识别行为的分析,提出r以2-PBI为基本骨架构建实用化比例计量型探针的途径。     

一种吡啶-水杨醛类席夫碱的合成及对Zn2+的特异性识别

通过席夫碱反应将2-氨基4-甲基吡啶与4-(二乙氨基)水杨醛结合,设计并合成出一种新型的荧光探针L,该探针能特异性识别Zn²⁺。通过质谱、¹H NMR以及¹³C NMR表征其结构,并利用荧光光谱、紫外-可见吸收光谱研究了探针L在CH₃OH-H₂O(V:V=8:2,Tris-HCl缓冲液,pH=7.4)中对各种离子的选择识别能力。实验结果显示,向探针L中加入Zn2+之后,溶液从无荧光变成蓝色荧光,且457 nm处出现一发射峰。Job’s plot工作曲线结果和密度泛函理论(DFT)计算表明探针L与Zn2+结合计量比为1:1。荧光滴定结果表明探针L对Zn2+的检测极限可低至2.7×10^-8 mol·L^-1,结合常数为1.32×10⁴ L·mol^-1,pH应用范围4.0～10.0。对真实水样中的Zn2+进行检测,平均回收率大于98%,RSD小于1.61%,表明探针L能够检测真实水样中的Zn2+。     

一种基于BODIPY的Zn~(2+)荧光探针:ICT增强效应

为克服BODIPY类探针Stokes位移小、发射偏短等不足,本文通过在BODIPY引入α-(4-羟基)苯乙烯基增强分子内电荷转移(ICT)效应并结合meso-位Zn2+螯合团的引入构建了一个发射红移到黄色的、有较大Stokes位移(~50 nm)的BODIPY类Zn2+荧光探针。这些特点有利于降低造影中自发荧光、光毒性和激发的干扰。光谱研究显示探针具有良好的Zn2+特异性荧光增强响应,且其他金属和近中性环境pH的干扰较小。该探针对Zn2+的线性响应范围为0.12~1.2μmol·L-1,检测限为0.18μmol·L-1。HeLa细胞内Zn2+共聚焦荧光成像研究表明该探针具有良好的细胞膜透过能力,可对胞浆内"自由"Zn2+实现可逆跟踪。     

锌-稀土矩形纳米簇的构筑及近红外发光性能（英文）

本文设计了一个新型含苯-甲基-苯骨架的席夫碱配体,构筑了两个具有矩形结构的锌-稀土纳米簇[Ln2Zn2L2(OAc)6](Ln=Yb(1)和Er(2))。该席夫碱配体以"伸展型"配位模式与稀土离子进行配位,使这些锌-稀土纳米簇表现出较大的分子尺寸结构(0.7nm×1.1 nm×2.2nm)。荧光性质研究表明,由Zn/L组成的发色基团能有效敏化1和2中Yb3+和Er3+离子的近红外发光。通过对荧光量子产率及寿命进行分析发现,Zn/L对Yb3+离子的传能效率要高于Er3+离子。     

基于羟苯基苯并咪唑的Zn2+比率荧光探针

通过羰基将两分子2-(4-氨基-2-羟苯基)苯并咪唑(4-AHBI)连接,合成了结构高度对称的新化合物N,N′-二-[3-羟基-4-(2-苯并咪唑)苯基]脲(C27H20N6O3,1),测试了不同溶剂条件下1的紫外吸收和荧光发射光谱,研究了1对Zn2+的选择性识别作用。结果表明,随着溶剂极性的增大,1的紫外吸收峰发生蓝移,激发态分子内质子转移(ESIPT)荧光发射峰明显增强。与4-AHBI相比,1在乙腈溶液中的紫外吸收强度增强约3.5倍,最大吸收峰红移8 nm,荧光发射增强8倍多。1在乙腈溶液中的Zn2+荧光响应行为表明1与Zn2+的结合将导致1在445 nm处的荧光强度不断降低,而在395 nm处出现的新峰的荧光强度不断增强,具有比率荧光探针的特点,而且检测范围较宽,可达1×10-6-1×10-2 mol.L-1。     

新型香豆素席夫碱化合物的合成及对锌离子的荧光传感研究

以3-氨基-6-氯香豆素为荧光发光基团,设计合成了3-[(2-羟基-苯亚甲基)-氨基]-6-氯香豆素(CHS)并研究其作为肉眼可视化荧光识别Zn2+的分子探针。采用元素分析和物理化学仪器如FTIR、1HNM R、紫外可见吸收和荧光光谱等手段表征了分子探针CHS的结构特征和理化性能。在CHS的二甲基甲酰胺溶液(DMF)中加入Zn2+后均会使溶液荧光显著增强,而溶液颜色由无色迅速转变为黄色,而且其它的金属离子对分子探针CHS识别Z n2+的影响不明显。通过Job图可以计算得出分子探针CHS与Z n2+之间形成1:1的稳定化合物,由Benesi-Hildebrand方程(采用吸收光谱计算)计算出分子探针CHS与Zn2+之间形成配合物的稳定常数为9.97×102mol/L。螯合荧光增强效应(CHEF)是导致分子探针CHS和CHD与Z n2+作用后荧光强度增强和吸收光谱红移的主要原因。在分子探针CHS的DMF溶液中加入Zn2+之后,荧光强度增强值与Zn2+的浓度在0~60μmol/L之间呈良好的线性关系,检出限为1.92μmol/L(r=0.9907,信噪比为3),表明分子探针CHS可用于定量检测微量Zn2+。     

基于缩硫醛脱保护机制的比例计量型Hg~(2+)荧光探针及其斑马鱼活体造影应用

利用汞离子特异性诱导缩硫醛脱保护,引发分子内电荷转移发生改变的机制,设计合成了一种新型的激发型比例计量汞离子荧光探针.该探针在与汞离子结合后其最大激发波长由410 nm红移至485 nm,两个波长下的荧光强比值(F485/F410)由0.06增长至5.02.同时该探针对汞离子表现出了良好的比例计量响应选择性和较快的响应速度,并且检测限低于美国环境保护组织的饮用水标准.共聚焦造影研究发现,该探针可以应用于活细胞及5天龄斑马鱼幼体中的汞离子的检测.利用该性质对Hg2+在斑马鱼体内分布及毒性进行了初步的研究.     

含均二苯乙烯荧光探针的合成及其对金属离子的识别研究

通过Wittig-Horner反应合成了两个含有均二苯乙烯发色团, 一端为N,N-双(2-乙酰氧乙基)氨基受体, 另一端分别为N,N-二甲氨基(DMDE)或N,N-二苯氨基(DPDE)的荧光探针分子. 进行了NMR和MS表征. 测试了加入不同金属离子时探针分子的吸收和荧光光谱变化. 加入Ag+和Zn2+, DMDE在420 nm处出现强的荧光峰, 在600 nm的荧光峰先增强后减弱, 认为发生了分子间的荧光共振能量转移. 而DPDE在加入Ag+和Zn2+, 420 nm处无荧光发射, 600 nm处的荧光红移并减弱.     

锌-稀土矩形纳米簇的构筑及近红外发光性能

本文设计了一个新型含苯-甲基-苯骨架的席夫碱配体,构筑了两个具有矩形结构的锌-稀土纳米簇[Ln₂Zn₂L₂(OAc)₆] (Ln = Yb (1)和Er (2))。该席夫碱配体以“伸展型”配位模式与稀土离子进行配位,使这些锌-稀土纳米簇表现出较大的分子尺寸结构(0.7 nm × 1.1 nm × 2.2 nm)。荧光性质研究表明,由Zn/L组成的发色基团能有效敏化1和2中Yb³⁺和Er³⁺离子的近红外发光。通过对荧光量子产率及寿命进行分析发现,Zn/L对Yb³⁺离子的传能效率要高于Er³⁺离子。     

A ratiometric fluorescent probe for zinc ions based on the quinoline fluorophore

A ratiometric fluorescent zinc probe 1 of carboxamidoquinoline with a carboxylic acid group was designed and synthesised. Probe 1 exhibits high selectivity for sensing Zn²⁺; about a 13-fold increase in fluorescence emission intensity and an 82?nm red-shift of fluorescence emission are observed upon binding Zn²⁺ in EtOH/H₂O (1?:?1, V/V) solution. The ratiometric fluorescence response is attributed to the 1?:?1 complex formation between probe 1 and Zn²⁺ which has been utilised as the basis for the selective detection of Zn²⁺. The analytical performance characteristics of the proposed Zn²⁺-sensitive probe were investigated. The linear response range covers a concentration range of Zn²⁺ from 2.0?×?10^?6 to 5.0?×?10^?5?mol?L^?1 and the detection limit is 2.7?×?10^?7?mol?L^?1. The determination of Zn²⁺ in both tap and river water samples shows satisfactory results.     

Development of ratiometric fluorescent probe for zinc ion based on indole fluorophore

A water-soluble ratiometric fluorescent probe ZID-1 has been developed on the basis of an internal charge transfer (ICT) mechanism. Upon complexation with Zn²⁺ under physiological conditions, ZID-1 exhibits a significant blue shift of 77 nm in the emission spectrum. The fluorescent behavior of ZID-1 suggests that the pyridyl group incorporated into the fluorophore coordinates the metal ion as the fourth ligand and affords an appropriate binding affinity (K_d = 17.1 nM) for the intracellular imaging of Zn²⁺.     

Ratiometric fluorescent Zn chemosensor constructed by appending a pair of carboxamidoquinoline on 1,2-diaminocyclohexane scaffold

By appending a pair of carboxamidoquinoline pendants onto 1,2-diaminocyclohexane scaffold via N-alkylation, multifunctionalized ACAQ was designed and synthesized as a water soluble fluorescent ratiometric chemosensor for Zn²⁺. In 50% aqueous methanol buffer pH 7.4 solution, upon excitation at 316 nm, ACAQ (5 μM) displayed a selective ratiometric fluorescence changes with a shift from 410 to 490 nm in response to the interaction with Zn²⁺. After binding with 1 equiv of Zn²⁺, ACAQ exhibited a 12-fold enhancement in I₄₉₀/I₄₁₀ characterized by a clear isoemissive point at 440 nm. The metal sensor binding mode was established by Job’s plot and the combined fluorescence and ¹H NMR spectroscopic method. The selectivity of the probe toward biological relevant cations and transition metal ions was proven to be good. In addition, the interference caused by Cu²⁺ and Cd²⁺ in the quantitation of Zn²⁺ can be completely eliminated by the use of diethyldithiocarbamate as the screening agent. Exploitation of ACAQ as the sensing probe, ratiometric determination of Zn²⁺ with the limit of detection (LOD) at 28.3 nm can be realized. In addition, the unique responsive properties of the probe toward Fe³⁺ and Zn²⁺ were used to construct a fluorescent switch. The membrane permeability of ACAQ to living cells and bio-imaging of Zn²⁺ were demonstrated.     

基于苯并噻唑Zn2+荧光探针及其细胞造影应用

设计合成基于苯并噻唑Zn²⁺荧光增强型探针BHP,在HEPES缓冲液中测其对Zn²⁺识别性能。实验结果表明,BHP对Zn²⁺有较高的选择性,对其他金属离子如Cd²⁺,Fe²⁺,Ni²⁺,Pb²⁺,Hg²⁺,Al³⁺,Mn²⁺,Ag⁺,Cu²⁺,Co²⁺,Na⁺,K⁺,Mg²⁺和Ca²⁺无明显荧光增强响应。BHP与Zn²⁺按1：1计量比配位,在生理条件下荧光强度不受pH值影响。在HeLa细胞中对Zn²⁺的造影表明BHP可用于生物体Zn²⁺检测。     

A FRET fluorescent chemosensor SPAQ for Zn based on a dyad bearing spiropyran and 8-aminoquinoline unit

A novel FRET fluorescent sensor SPAQ containing 8-aminoquinoline (donor) and spiropyran derivative (acceptor) was designed and synthesized for detecting Zn²⁺. The probe successfully exhibited a fluorescence turn on and ratiometric response for Zn²⁺ in ethanol solution with high selectivity. Upon excitation at 370 nm, the modulation of the emission intensity of SPAQ at 645 and 470 nm was achieved in the presence of Zn²⁺ by fluorescent resonance energy transfer (FRET) and chelation-enhanced fluorescence (CHEF) effects.     

A highly selective ratiometric fluorescent chemosensor for Zn2+ ion based on a polyimine macrocycle

A new ratiometric fluorescent chemosensor based on a polyimine macrocycle ligand 1 has been synthesized. The chemosensor can exhibit a pronounced fluorescence response and high selectivity to Zn²⁺ ion over other 15 metal ions, including Cd²⁺. Sensor 1 appears an emission peak at 370 nm. Upon the addition of Zn²⁺ ion, the typical emission peak for 1 at 370 nm is obviously quenched, but a new emission peak at around 470 nm appears and shows a large enhancement due to the formation of a 1:1 Zn²⁺-1 complex. In addition, there is a good linear relationship between the fluorescence ratio I_470nm/I_370nm and the concentration of Zn²⁺, which makes a ratiometric assay of Zn²⁺ ion possible.     

Synthesis and photophysical properties of a fluorescent TREN-type ligand incorporating the coumarin chromophore and its zinc complex

A new, UV-excited fluorescent Zn²⁺ indicator was synthesized and the spectral profile of its free and Zn²⁺ bound forms were studied. The fluorescent properties of this probe are due to the 7-amino-4-methylcoumarin fluorophore, which is conjugated with the tris(2-aminoethyl)amine (TREN) that functions as the zinc-chelating moiety. The compound exhibits a Zn²⁺ dissociation constant of 18.0 μM. The fluorescence spectra of the probe showed a clear shift in excitation wavelength maxima upon Zn²⁺ binding, indicating its potential use as ratiometric Zn²⁺ indicator.     

Construction of Fluorescent Probes Via Protection/Deprotection of Functional Groups: A Ratiometric Fluorescent Probe for Cu2+

Herein a ratiometric fluorescent Cu²⁺ probe was rationally constructed in a straightforward manner with the concept of aldehyde group protection/deprotection. The probe showed a ratiometric fluorescent response to Cu²⁺ with a large emission wavelength shift (>100 nm) and displayed high selectivity for Cu²⁺ over other metal ions due to distinct deprotection conditions. In addition, a Cu²⁺‐promoted dethioacetalization mechanism was proposed.     

Two new fluorescent Zn2+ sensors exhibiting different sensing mode with subtle structural changes

Two novel receptors HL-1 and HL-2 without and with hydroxyl groups were designed and synthesised. Both receptors showed highly selective coordination towards Zn²⁺ and exhibited diverse sensing behaviour due to the structural variations. HL-1 showed monotonous ‘turn-on’ response towards Zn²⁺ while HL-2 displayed highly Zn²⁺ sensitive ‘turn on’ and ‘ratiometric’ properties. Detailed Job plot experiment, single crystal data, ¹H NMR, ESI-MS, UV–vis and density functional theory calculation studies were conducted to understand the binding modes of HL-1 and HL-2 with Zn²⁺. These results revealed the binding stoichiometric ratio between receptors and Zn²⁺ were 1:1 with low detection limits and high binding constants.     

Fluorescent carbazolyldithiane as a highly selective chemodosimeter via protection/deprotection functional groups: a ratiometric fluorescent probe for Cd(II)

A carbazole-based bis-dithiane (1) was rationally constructed in a straightforward manner for the selective and ratiometric fluorescent detection of Cd²⁺ with the concept of aldehyde group protection/deprotection. The probe showed a ratiometric fluorescent response to Cd²⁺ with a large emission wavelength shift (>50 nm) and displayed high selectivity for Cd²⁺ over other metal ions due to distinct deprotection conditions. In addition, a Cd²⁺-promoted dethioacetalization mechanism was proposed.