A rhodamine derivative for Hg2+-selective colorimetric and fluorescent sensing and its application to in vivo imaging

A rhodamine-based sensor has been developed for the detection of mercuric ions. The colorimetric and fluorescence responses, allowing naked-eye detections, are based on Hg~(2+)-induced opening of the rhodamine spirocycle. Among all the testes ions, only Hg~(2+)generated a significant fluorescence enhancement of up to 300-fold, with a bright yellow–green emission. This sensor was a low toxic compound, and was successfully applied in the in vivo imaging of Hg~(2+)in Spill 2 cells and C. elegans. This approach provides a sensitive and accurate method for the estimation of Hg~(2+)in environmental, tobacco and biological applications.     

A colorimetric chemosensor based on new water-soluble PODIPY dye for Hg2+ detection

The phosphorus-containing PODIPY 1 as a chemosensor can detect Hg~(2+) by a color change from pink to violet red without the use of any instrumentation. PODIPY 1 was selective to Hg~(2+)with a remarkable absorption change, and addition of other relevant metal ions caused almost no absorption change. The new PODIPY dye 1 was sensitive to various concentrations of Hg~(2+). The energy gap between the HOMO and LUMO of the metal complex 1–Hg~(2+)is smaller than that of chemosensor 1, which is in good agreement with the red shift in the absorption observed upon treatment of 1 with Hg~(2+). The 1-based test strips were easily fabricated and low-cost, useful in practical and efficient Hg~(2+)test kits.     

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.     

Selective transport of silver ions through bulk liquid membrane using Victoria blue as carrier

Transport of Ag⁺ as Ag(CN)₂⁻ ions through a bulk liquid membrane is reported. The bulk liquid membrane used is a solution of Victoria blue (VB) in chloroform. The effects of pH of the source phase, cyanide concentration in the source phase, sodium hydroxide in the receiving phase, and VB concentration in the organic phase on the efficiency of the transport system were studied. The above system has a high selectivity for Ag⁺ and can selectively and efficiently transport Ag(CN)₂⁻ ion from aqueous solutions containing other cations such as alkali and alkaline earths, Zn²⁺, Pd²⁺, Cu²⁺, Cd²⁺,Hg²⁺, Co²⁺, Fe²⁺, Pb²⁺, Ni²⁺, and Al³⁺.     

A Fluorescent and Colorimetric Probe Based on Isatin-appended Rhodamine for the Detection of Hg2+

A new fluorescent probe for the detection of Hg²⁺ was designed and synthesized via attaching N-methylisatin to rhodamine B hydrazide through an imine linkage. In an ethanol-Tris buffer medium, the addition of Hg²⁺ caused a strong orange fluorescence and a visual color change from colorless to pink. Other coexisting metal ions did not interfere with the detection of Hg²⁺. The research on the detection of Hg²⁺ in natural water suggested the possibility of practical applications in environment monitoring. Based on ESI-MS analysis, the Hg²⁺-sensing mechanism was proposed.     

Cation selectivity of ionophores based on tripodal thiazole derivatives on benzene scaffold

The synthesis and potentiometric evaluation of new 1,3,5-tris(thiazolylcarbethoxy)-2,4,6-trimethylbenzene (3), 1,3,5-tris(thiazolylhydroxy)-2,4,6-trimethylbenzene (4), 1,3,5-tris(thiazolylmethyl)-2,4,6-trimethylbenzene (5), and 1,3,5-tris(thiazolylphenyl)-2,4,6-trimethylbenzene (6), toward mono and divalent cations under various pH conditions are outlined. The ion-selective properties of the newly synthesized compounds were studied by measuring the potentiometric responses of the 3-, 4-, 5-, and 6-based membrane electrodes to alkali metal, alkaline earth metal, ammonium, and transition metal ions, under various pH conditions. The 3-based electrode exhibited a Nernstian response to ammonium and potassium under alkaline pH conditions, while the other three electrodes showed a poor potentiometric performance. All electrodes showed substantial responses to silver ion under acidic condition, but there was almost nil response to other transition metal ions (Fe²⁺, Co²⁺, Zn²⁺, Ni²⁺, Pb²⁺, Cd²⁺, Cu²⁺ and Hg²⁺). The 3- and 5-based electrodes resulted in near Nernstian responses (51.3 mV and 59.5 mV/pAg⁺, respectively) with low detection limits (100 ppt), while the 4- and 6-based ones showed sub-Nernstian below 40 mV/pAg⁺. The results were interpreted with semi-empirically modeled structures.     

A new rhodamine-based fluorescent chemosensor for mercury in aqueous media

A new fluorescent ‘‘on–off' chemosensor for Hg2+initiated by a derivative of rhodamine B was designed and synthesized. Compound 1 exhibited high sensitivity and selectivity for Hg2+over other commonly coexistent metal ions in aqueous media. Upon the addition of Hg2+, the spirocyclic ring of probe is opened and a significant enhancement of visible color and fluorescence in the range of 500–600 nm is observed. The colorimetric and fluorescent response to Hg2+can be conveniently detected by the naked eye, which provides a facile method for visual detection of Hg2+. From the molecular structure and spectral results of 1, an irreversible, hydrolysis, desulfurization reaction mechanism is proposed.     

A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions

We develop a novel coumarin-alkyne derivative(NC7-AL), which can specifically react with Au~(3+) and give a colorimetric and fluorescent ‘‘turn-on' response toward Au~(3+). Notably, other alkynophilic metal species such as Au+, Ag+, Pd~(2+), Ni~(2+), Cu~(2+), and Hg~(2+) do not produce an interfering signal. A good linear relationship between emission intensity at 420 nm and Au~(3+) concentration from 0 to 2 equivalent is observed, and the detection limit(3s/k) is estimated to be ca. 3.58 nmol/L. Harnessing the Au~(3+)-induced color change from light yellow to colorless, we find that NC7-AL-based modified TLC plate can be used for convenient naked-eye detection of Au~(3+).     

A squaraine based fluorescent probe for mercury ion via coordination induced deaggregation signaling

Due to the high affinity between dithiocarbamate(DTC) and Hg2+,a fluorescent probe based on squaraine chromophore with DTC side arm for Hg2+via coordination induced deaggregation signaling has been designed and synthesized.Squaraine has a high tendency to aggregate in aqueous solution,and such self-aggregation usually results in a dramatic absorption spectral broadening with fluorescence emission quenching.The combination of the DTC side arm of the probe with Hg2+induces steric hindrance,leading to the deaggregation of the dye complex,companying with a fluorescence emission restoration.In EtOH–H2O(20:80,v/v) solution,this ‘‘turn on' fluorescent probe has high selectivity and sensitivity toward Hg2+over other metal ions,and the limit of detection for Hg2+was estimated as2.19 ? 10à8mol/L by 3s/k.     

电沉积紫膜薄膜中菌紫质的光电响应对N-端表面的金属阳离子浓度的依赖性

用不锈钢/电沉积紫膜薄膜/含水胶(电介质)/钢型菌紫质光电池研究了作用于N-端表面(紫膜外表面)的钾、镁、镧离子对菌紫质光电响应的影响。在所测条件下光电极性均与质子泵方向一致。光电压幅值是离子浓度依赖性的,对钾、镁、镧离子均存在极大值浓度,它们之间有数量级的差异;依赖性曲线趋势和极大值浓度均各自分别与溶液中菌紫质的质子泵效率对阳离子浓度的这种依赖性相一致。不过,光电响应对作用于C-端表面的这些离子不存在上述的浓度依赖性。上述的两种依赖性成相关性说明:电沉积紫膜薄膜中菌紫质的光电响应主要来自质子泵运而非非质子离子的贡献;存在一合适的离子浓度使菌紫质的光电响应有极大值。用质子泵结构域模型和扩散双电层理论对这种依赖性进行的讨论认为:金属阳离子的结合与屏蔽两种效应可以解释这种依赖性。     

Fluorescent peptide sensor for the selective detection of Cu

A new fluorescent peptidyl chemosensor for Cu²⁺ ions with fluorescence resonance energy transfer (FRET) capabilities has been synthesized via Fmoc solid-phase peptide synthesis. The metal chelating unit, which is flanked by the fluorophores tryptophan (donor) and dansyl chloride (acceptor), consists of the amino acids glycine and aspartic acid (Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly). Coordination of the Cu²⁺ ions to the metal chelating unit results in fluorescent quenching of both the donor and acceptor fluorophores. Although it was determined that Cu²⁺ binding causes no change in FRET efficiency, emission and Cu²⁺-induced quenching of the acceptor dye can be used to monitor the concentration of the copper ions, with a detection limit of 32 μg L⁻¹. The sensor also demonstrated sensitivity, reversibility and selectivity towards Cu²⁺ in a transition metal matrix at pH 7.0.     

Influence of K+, Na+ or Ca2+ Ions on the Interaction Between AmB and Saturated Phospholipids by Langmuir Technique

Interaction between amphotericin B(AmB) and cell membrane is influenced by different metal cations. In the presence of K⁺, Na⁺ or Ca²⁺ ions, the surface pressure-area isotherms and the elastic modulus of an amphotericindipalmitoylphosphatidylcholine(AmB-DPPC) mixed monolayer were discussed. And the excess free energy and entropies of mixing were calculated according to the surface pressure-area isotherms. The phase transition of the mixed monolayer needed a higher concentration of AmB in the sequence Na⁺ > pure buffer > K⁺ > Ca²⁺. When the molar fraction of AmB(x_AmB) was 0.5, the molecular interaction changed from attraction to repulsion and the mixed monolayer turned to ordered state from disorder state under the induction of K⁺ or Ca²⁺ ions at all surface pressure in our experiment. At high surface pressure, the disorder of monolayer enhanced in the presence of Na⁺ ions at x_AmB > 0.1. At different molar ratios of AmB, the influences of these metal cations were discrepant. These cations may influence AmB molecules to form pores on the monolayer. It is helpful to understand the reduction of AmB's toxicity as theoretical reference.     

几种过渡金属离子与苏丹Ⅰ(1-苯基偶氮基-2-萘酚)形成配合物的13C核磁共振研究

目前用核磁共振测定配合物结构的报道很多,J。Blackburn等人曾用NMR做为研究电子施主-受主配合物结构的探针^[1],也有人曾用弛豫速率研究胰朊酶的钙键位置^[2]。但随过渡金属离子的逐渐加入形成配合物的NMR研究报道尚不多,本文利用苏丹Ⅰ与一些过渡金属离子形成配合物后¹³C化学位移的变化,并以红外光谱、紫外-可见光谱为佐证研究了这些配合物的结构,并用多种方法对苏丹Ⅰ骨架的¹³CNMR谱进行了归属,初步探讨了,苏丹Ⅰ分子¹³C屏蔽机理及化学位移与分子电子结构间的关系。     

UiO-66-NH2/wood的设计构筑及高效去除水中微量重金属离子性能

矿山开采、 金属冶炼、 新型金属材料的发展以及城市供水系统老化所造成的重金属(铅、 镉、 汞、 砷、 铬、 铜及锌等)污染问题已日趋严重. 传统的水处理方法很难有效地去除低浓度的重金属污染物. 本文以天然木材为载体, 采用溶剂热合成法, 在木材三维孔道中原位合成UiO-66-NH₂金属有机框架材料(MOFs)纳米颗粒, 制备了UiO-66-NH₂/wood复合膜材料. 该复合膜材料对去除水中微量重金属离子(Hg²⁺, Cu²⁺)表现出优异的性能. 当处理速率为1.1×10² L?m^-2?h^-1时, 该复合膜材料去除水中微量重金属离子的效率仍可达到90%以上, 且处理后水中重金属离子含量低于国家饮用水标准. 这可归因于木材本身独特的三维孔道结构, 在提高水通量的同时, 还可以增加水溶液中重金属离子与MOFs颗粒的接触机会, 以及孔道内均匀分布的UiO-66-NH₂ MOFs颗粒中的—NH₂可以与重金属离子通过配位作用相结合. 该UiO-66-NH₂/wood复合膜材料还具有良好的重复利用性, 在连续6次循环使用后其去除效率无明显变化, 有望进行实际应用.     

湿法脱硫浆液中Hg2+的还原机制研究

针对燃煤电厂湿法脱硫浆液中Hg²⁺易被还原的特性,研究Hg²⁺在模拟湿法脱硫系统中的迁移机制,考察了浆液温度、pH值以及SO₃^2-、Cl^-、Ca²⁺、Mg²⁺浓度等因素对Hg²⁺还原性能的影响。结果表明,Hg²⁺还原率随着浆液中SO₃^2-浓度的增大而降低;pH值对Hg²⁺的还原呈先增加后降低的趋势,在pH值为5.5时还原率最高;温度的升高不利于浆液中稳定的二价汞盐络合物存在,导致Hg²⁺还原率增加;Ca²⁺、Mg²⁺以及Cl^-浓度的增加有利于形成稳定化合物,从而抑制Hg²⁺的还原。     

Rhodamine 6G-based Chemosensor for the Visual Detection of Cu2＋ and Fluorescent Detection of Hg2＋ in Water

A novel water soluble chemosensor 1 based on rhodamine 6G spirolactam scaffold has been synthesized and characterized.Upon addition of a wide range of the environmentally and biologically relevant metal ions,chemosensor 1 shows a colorimetric selective Cu2＋ recognition from colorless to pink confirmed by UV-Vis absorption spectral changes,while it also exhibits a fluorometric selective Hg2＋ recognition by fluorescence spectrometry.An absorption enhancement factor over 17-fold with 1-Cu2＋ complex and a fluorescent enhancement factor over 45-fold with 1-Hg2＋ complex were observed.Their recognition mechanisms were assumed to be a 1：1 stoichiometry for 1-Cu2＋ complex and a 1：2 stoichiometry for 1-Hg2＋ complex,respectively,which were proposed to be different ligation leading to the ring-opening of rhodarnine 6G spirolactam.Furthermore,the detection limits for CU2＋ or Hg2＋ were 3.3 × 10-8 or 1.7x 10-7 mol/L,respectively.     

锰负载钛锆和钛锡复合氧化物催化剂烟气脱汞实验研究

采用共沉淀法制备了TiO_2、TiZr和TiSn载体,浸渍锰制备了10%MnO_2的MnTi、MnTiZr和MnTiSn催化剂。采用BET、XRD、H_2-TPR、FT-IR和XPS等对样品进行表征,并对三种催化剂进行固定床脱汞性能实验。结果表明,在100-300℃,MnTiZr和MnTiSn催化剂脱汞性能均优于MnTi催化剂,这归因于Sn和Zr的引入提升了催化剂比表面积和低温氧化还原性能增加了催化剂表面的酸性位点数量、高价态锰离子和O~*含量;在反应温度为150-300℃,MnTiSn催化剂脱汞效率均高于MnTiZr催化剂这是由于前者具有更好的氧化还原性能,表面具有更多含量的高价态锰离子、O~*含量和酸性位点数量;在Hg~0脱除过程中催化剂表面活性组分如高价态锰离子和O~*均消耗,参与了Hg~)氧化为Hg~(2+)的反应且MnTiSn催化剂表面活性组分的消耗量更多。     

A highly selective chemosensor for copper ion based on ICT fluorescence

Simple structural compounds 1 to 3 were synthesized.The presence of Cu²⁺ resulted in the fluorescence and absorption spectra change of 1 and 2,which indicated that 1 and 2 showed a highly selective response to Cu²⁺ over other metal ions.However,3 showed no selectivity for metal ions,which means that the compound could bind with several metal ions,such as,Ni²⁺,Zn²⁺,Cd²⁺.Hg²⁺, Pb²⁺,Fe³⁺,Mg²⁺,Ca²⁺,and Co²⁺,except Cu²⁺ and Ag⁺.The different spectral responses were attributed to the difference in binding sites for 1 and 3.     

Synthesis and properties of three novel rhodamine-based fluorescent sensors for Hg2+

Three novel rhodamine-based Hg~(2+) fluorescent sensors were designed and synthesized. The sensors could work in semi-aqueous solutions with nearly neutral p H and showed high selectivity and sensitivity to Hg~(2+) with remarkable fluorescence enhancement. For these three sensors, the linear working range broadened(0–80, 0–100 and 0–140 μmol/L, respectively) and the sensitivity increased(7.7, 15.5 and 17.6 folds of the fluorescence enhancement and 512, 66.2 and 37.6 ppb of the detection limit) with the rising of the thiourea-unit numbers. Furthermore the sensors exhibited excellent interference immunity to multiple environmentally and biologically relevant metal ions. Pond and tap water assay showed good practicability of the sensors. The number of the bound Hg~(2+) equaling to that of the thiourea units and the irreversible recognition process implied a new interaction way between Hg~(2+) and the sensor.     

REGENERATION OF BLUE AND PURPLE MEMBRANES FROM DEIONIZED BLEACHED MEMBRANES OF Halobacterium halobium

Abstract— Bleached purple membrane normally binds Ca²⁺ and Mg²⁺, which can be removed by the divalent cation chelator ethylenediaminetetraacetic acid (EDTA). Regeneration of pigments from EDTA-treated bleached membrane (apomembrane) and retinal leads to the formation of blue membrane at pH 4.8, and purple membrane at neutral pH. The pigments take much longer to regenerate than with un-deionized apoprotein. Adding back cations to the deionized apomembrane only partially speeds up the regeneration process. Like native purple membrane, the regenerated purple membrane also undergoes a photocycle and shows a light-induced proton release and uptake, although with much slower kinetics than the native species. Thus, cations control the kinetics of pigment regeneration, and also some aspects of the pigment's conformation which controls the photocycle kinetics. The removal and replacement of the cations is not completely reversible, suggesting the cations are not merely bound in the double layer.