首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 171 毫秒
1.
合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn2+荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn2+具有良好的识别性能,同时相对于Ca2+, Cd2+, Co2+, Cu2+, Hg2+, Fe3+, Mn2+, Ni2+, Pb2+等金属离子具有良好的选择性。  相似文献   

2.
CdS/MS(M=Ag,Pb,Cu,Zn)半导体纳米复合结构的制备   总被引:5,自引:0,他引:5       下载免费PDF全文
利用金属硫化物在水溶液中溶度积的差异和通过水热及超声波等辅助方式,利用离子置换法与共沉淀法,对CdS纳米棒上金属离子(Cd2+)的部分置换而对纳米微粒进行侵蚀或包覆,形成镶嵌式点缀结构或完全包覆层的异质核-壳结构CdS/MS(M=Ag+,Cu2+,Pb2+,Zn2+)。使用XRD和TEM对所得样品进行了表征。  相似文献   

3.
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。  相似文献   

4.
乳状液膜法迁移及分离钯(Ⅱ)的研究   总被引:4,自引:0,他引:4  
本文采用以叔胺N7301为流动载体、span 80为表面活性剂、煤油为膜溶剂、EDTA作内相试剂的乳状液膜体系迁移分离钯(Ⅱ)。确证了其迁移机理。实验表明在所筛选出的适宜制乳及迁移分离等最佳条件下,96%以上的Pd(Ⅱ)迁入内相,并能有效地与Cu2+、 Zn2+、Cd2+、Pb2+、Ni2+、Fe2+等离子分离。  相似文献   

5.
设计合成了带有羟基取代的希夫碱配体化合物1,并研究了它与Zn2+的识别。结果发现:在乙腈溶剂中化合物1与Zn2+络合后有强的荧光发射,而化合物1除了与Mg2+络合后有弱的荧光发射被检测到外,与其他离子(Fe2+, Co2+, Ni2+, Cu2+, Cd2+, Hg2+, Pb2+, Ca2+, Ba2+, Sr2+)络合后未检测到荧光发射。研究结果还表明:化合物1能在多组分混合离子中对Zn2+进行选择性检测而不受其他离子的干扰。为了弄清配体化合物1与Zn2+络合的反应机理,本论文还设计合成了其他三个带羟基取代的希夫碱配体化合物2-4,并分别研究了它们与Zn2+的识别。  相似文献   

6.
为了研究非配位型溶剂对聚酰胺-胺(PAMAM)树形分子的模板法制备CdS量子点的影响, 分别以水、甲醇及二者的混合物( ∶ =2∶1)为溶剂, 以4.5代PAMAM树形分子为模板制备了CdS量子点. 结果表明, 相同条件下, 以甲醇为溶剂时制备的CdS量子点为单晶, 平均直径2.7 nm, 尺寸分布窄, 发光强度高; 以水为溶剂制备的CdS量子点为多晶, 平均直径为5.7 nm, 尺寸分布宽, 发光强度低; 在甲醇与水的混合溶剂中制备的CdS量子点为单晶和多晶共存, 平均直径为4.1 nm, 尺寸分布及发光强度都居中. 这主要是由于树形分子的模板作用不同造成的. 树形分子在甲醇中能充分伸展, 起到内模板作用; 树形分子与水之间由双氢键作用而产生交联, 不利于Cd2+与树形分子内部基团的配位, 主要起到外模板作用; 在甲醇与水的混合溶剂中, 树形分子则同时起到了内模板和外模板作用.  相似文献   

7.
有机化合物因成膜以后荧光淬灭而使其应用受到很大限制, 所以研究、开发能在聚集状态下呈现优异发光性能的新材料就尤为重要. 由于分子间π-π和极性共同相互作用, 使得磷酰杂菲环的转动受到限制, 从而使苯甲酸-2-[6-氧化-6-氢-二苯基(c,e)<1,2>氧杂磷酰基]-1,4-二羟基苯二酯(OP)在达到一定规整聚集程度时, 荧光强度成倍增加, 具有了聚集诱导发光增强(AIEE)性质. 实验结果表明: 浓度低于1×10-6 mol•L-1 的OP会失去AIEE性质; 浓度为1×10-4 mol•L-1的Hg2+, Fe2+和 Fe3+会分别淬灭浓度为1×10-5 mol•L-1 OP荧光强度的26%, 34%, 74%, 而Pb2+, Zn2+, Cd2+, Co2+, Mn2+, Cu2+, Ni2+, Ag等离子的淬灭效率却很低, 这一性质表明该化合物可以用作过渡金属离子的特异性检测材料.  相似文献   

8.
 由聚环硫氟丙烷与多乙烯多胺反应制得的聚合物(PB)再与环硫丙烷反应,合成了四种以聚硫醚为主链的异丙巯基胺树脂(PBM1-4)。树脂对Au3+、Pd2+、Pt4+、Ag+和Hg2+等离子具有强的吸附能力,对Cu2+次之,对Zn2+和Pb2+很弱。树脂对贵金属具有高的选择性,能从含Au3+、Cr3+、Co2+、Ni2+、Cu2+、Mn2+、Zn2+和Fe3+的溶液中定量吸附Au3+而不吸附其它离子。  相似文献   

9.
制备了具有高荧光量子产率(photoluminescence quantum yield, PLQY)的 Mn2+掺杂准二维钙钛矿(PEA)2PbyMn1-yBr4(PEA为苯乙胺, y 为 Pb2+占 Mn2+和 Pb2+总含量的物质的量分数)薄膜。宽带隙的(PEA)2PbBr4作为给体, 掺杂杂质 Mn2+作为受体, 构筑了双发射的激发态传递系统。通过调控 Mn2+掺杂的不同比例对(PEA)2PbyMn1-yBr4的发光性能和薄膜形貌的影响, 发现当前驱体溶液中 Mn2+与 Pb2+的物质的量之比为 1:4 时, 薄膜有着最高的 PLQY 和最低的表面粗糙度。利用飞秒瞬态吸收(transientabsorption, TA)光谱, 追踪其动力学过程, 发现主客体之间的激发态传递是通过电荷转移来实现的。为了研究材料的电致发光特性, 我们将(PEA)2PbyMn1-yBr4作为活性层, 加工得到了发光二极管(light emitting diodes, LEDs)。在室温下, 器件发出明亮的橙色, 其最高的发光强度为 0.21 cd·m-2, 外量子效率(external quantum efficiency, EQE)为 0.002 5 %。  相似文献   

10.
合成并表征了1,10-二氧-4,7,13,16-四氮杂18-冠-6 (1)母体及其四取代硝基酚臂式衍生物 (2)。在H2O-DMSO(V/V=1/4)混合溶剂中用UV-Vis光谱法对冠醚2与H+、Mn2+、Co2+、Ni2+、Cu2+、Zn2+、Cd2+和Hg2+相似文献   

11.
丛日敏  罗运军  靳玉娟 《化学学报》2007,65(21):2479-2483
为了研究温度对聚酰胺-胺(PAMAM)树形分子的模板法制备硫化镉(CdS)量子点的影响, 以4.5代(G4.5, 64个甲酯端基)PAMAM树形分子为模板, 在-10~30 ℃的温度范围内制备了分散良好的CdS量子点. 用透射电子显微镜(TEM)表征了CdS量子点的形貌、尺寸; 用紫外-可见光谱(UV-Vis)和光致发光光谱(PL)表征了CdS量子点的光学性能. 发现在相同条件下, 制备温度从-10 ℃升高到30 ℃, CdS量子点粒径从1.8 nm增大到3.4 nm, 其中在10 ℃时制备的量子点的尺寸分布最窄; CdS量子点的吸收和发射光谱均随温度增大而红移, 其中10 ℃时制备的量子点的室温光致发光效率最高. 这表明制备温度决定了树形分子的配位基团与Cd2+的分离速度, 并影响了CdS量子点的成核和生长过程, 从而最终决定了CdS量子点的尺寸及尺寸分布、光致发光颜色和发光效率.  相似文献   

12.
以4、5代PAMAM树形分子(64个酯端基)为模板, 在树形分子空腔内原位合成了CdS-ZnS核-壳结构量子点, 并对其形貌和光学性能进行了表征. HRTEM观察发现量子点分散良好, 尺寸均匀, 平均粒径约为2.3 nm. UV-Vis光谱证明ZnS外延生长在CdS核外, EDS能谱也证明了核壳结构的生成. 适当厚度的ZnS壳层可使光致发光效率提高至31%. PAMAM树形分子包在CdS-ZnS核-壳结构量子点外, 构成一层有机壳, 有效地限制了粒子聚集, 钝化了CdS量子点表面, 提高了发光效率. 另外, PAMAM树形分子良好的溶解性也赋予了量子点在不同极性溶剂中良好的溶解性, 提高了其稳定性.  相似文献   

13.
The paper reports on the spectral photophysical characteristics of two new fluorescent PAMAM dendrimers of zero and second generation decoreted with 1,8-naphthalimide units, designed for ionic detection. The dendrimers were studied by (1)H NMR, (13)C NMR, FT-IR spectroscopy and elemental analysis. Their ability to detect ions has been evaluated in acetonitrile by monitoring the quenching of the fluoresence intensity. Different ions have been tested: Zn(2+), Co(2+), Ni(2+), Cu(2+) and Fe(3+) for the purpose. The results have shown clearly that only Zn(2+) could be efficiently detected using the dendrimer of second generation. In addition, it has been shown that for both dendrimers in a acetonitrile-water solution, the fluoresence intensity is pH dependant, hence could find application as a detector of harmful pH changes in the environment.  相似文献   

14.
将荧光猝灭基团修饰的17E脱氧核酶(17E DNAzyme)与荧光基团修饰的底物链通过6个脱氧核苷酸相连, 得到了一种新型的对Pb2+敏感的荧光探针. 由于DNAzyme与底物链发生分子内杂交, 荧光基团与猝灭基团相互靠近, 导致荧光猝灭. 当Pb2+存在时, DNAzyme被激活, 底物链被切断后释放出荧光基团标记的DNA片段, 从而产生明显的荧光信号. 据此可在常温下快速检测Pb2+, 检测下限为10 nmol/L. 在Zn2+, Mn2+, Co2+, Cd2+, Cu2+, Mg2+和Ni2+等多种二价金属离子中, 除Zn2+, Mn2+和Cd2+略有干扰外, 其它几种金属离子均无响应, 表明该荧光探针对Pb2+具有良好的选择性.  相似文献   

15.
CdS半导体纳米簇具有独特的光、电性能, 如何制备均匀分散的、能够稳定存在的CdS纳米簇是目前的研究热点之一. 以聚酰胺-胺(PAMAM)树形分子为模板, 原位合成了CdS纳米簇. 首先用UV-Vis分光光度法研究了与树形分子的配位机理, 得出G4.5和G5.0的平均饱和配位数分别为16和34, 并发现在G4.5PAMAM树形分子中Cd2+主要与最外层叔胺基配位, 在G5.0PAMAM树形分子中Cd2+主要与最外层伯胺基配位. 酯端基的G4.5的模板作用要明显优于胺端基的G5.0. 通过改变Cd2+与G4.5树形分子的摩尔比可以得到不同粒径的CdS纳米簇. 溶液的pH值对CdS纳米簇影响很大, pH在7.0左右制备的CdS纳米簇粒径小而均匀, 且溶液稳定性高. 用UV-Vis分光光度计和TEM对CdS纳米簇的大小和形貌进行了表征. 结果表明TEM观测CdS纳米簇的粒径要大于用Brus公式的估算值.  相似文献   

16.
将8-17 DNAzym e增加2个"G-C"碱基对进行增强热稳定性的结构修饰,并标记上1个荧光基团"FAM"和2个荧光猝灭基团"Dabcyl",设计成双猝灭Pb2+荧光探针。研究了该探针对Cd2+、Zn2+、Mg2+、Cu2+、Mn2+、Pb2+6种二价金属离子的响应,结果表明探针对Pb2+具有很强的特异性,在探针浓度为2.5×10-7mol/L时,Pb2+浓度在8.5×10-8~7.5×10-6mol/L范围内和探针的荧光强度呈线性关系,检出限为8.5×10-8mol/L。该探针可用于Pb2+的定性和定量检测。  相似文献   

17.
Highly fluorescent water-soluble CdSe/ZnS (core/shell) quantum dots (QDs) as a fluorescent Cu2+ ion probe were synthesized using thiacalix[4]arene carboxylic acid (TCC) as a surface coating agent. Hydrophobic trioctylphosphine oxide (TOPO) capped CdSe/ZnS QDs were overcoated with TCC in tetrahydrofuran at room temperature, and deprotonation of the carboxyl groups of TCC resulted in the formation of water-soluble QDs. The surface structure of the QDs was characterized by using transmission electron microscopy (TEM) and fluorescence correlation spectroscopy (FCS). TEM images showed that TCC-coated QDs were monodispersed with the particle size (core-shell moiety) of approximately 5 nm. Hydrodynamic diameter of the TCC-coated QDs was determined to be 8.9 nm by FCS, showing that the thickness of the surface organic layer of the QDs was approximately 2 nm. These results indicate that the surface layer of TCC-coated QDs forms a bilayer structure consisting of TOPO and TCC molecules. TCC-coated CdSe/ZnS QDs were highly fluorescent (quantum yield, 0.21) compared to the QDs surface-modified with mercaptoacetic acid and mercaptoundecanoic acid. Fluorescence of the TCC-coated QDs was effectively quenched by Cu2+ ions even in the presence of other transition metal ions such as Cd2+, Zn2+, Co2+, Fe2+, and Fe3+ ions in the same solution. The Stern-Volmer plot for the fluorescence quenching by Cu2+ ions showed a linear relationship up to 30 microM of Cu2+ ions. The ion selectivity of TCC-coated QDs was determined by measurements of fluorescence responses towards biologically important transition metal ions (50 microM) including Fe2+, Fe3+, Co2+>Zn2+, Cd2+. The fluorescence of TCC-coated QDs was almost insensitive to other biologically important ions such as Na+, K+, Mg2+, and Ca2+, suggesting that TCC-coated QDs can be used as a fluorescent Cu2+ ion probe for biological samples. A possible quenching mechanism by Cu2+ ions was also discussed on the basis of a Langmuir-type adsorption isotherm.  相似文献   

18.
Highly photoluminescent hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposites latex were prepared by using the chelating copolymer, poly(methyl methacrylate-co-methyl acrylate-co-2-methyl acrylic acid 3-(bis-carboxymethyl amino)-2-hydroxyl-propyl ester), with in-situ chemical precipitation method. The morphology and photoluminescence property of the hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposites latex was examined by TEM and photoluminescence analyzer (PL), respectively. The photoluminescent intensity of the hybrid CdS nanocluster/copolymer nanocomposites could be enhanced by Zn(II) doped treatment from the PL measurement. Furthermore, these hybrid nanocomposite latex could be easily manufactured into the transparent nanocomposite membrane without losing their photoluminescence property as they were cured at 60 °C. Interestingly, the photoluminescence property of the hybrid Zn(II)-doped CdS nanocluster/copolymer nanocomposite membranes would be influenced by amino compounds due to the surface passivation effect. When the secondary amine compounds were used as the surface passivation materials, the photoluminescent intensity of the hybrid nanocomposite membrane would be enhanced. On the contrary, the hybrid nanocomposite membranes would descend their photoluminescent intensity as the primary amine compounds were used as surface passivation materials.  相似文献   

19.
Strong luminescence CdS quantum dots (QDs) have been prepared and modified with l-cysteine by a facile seeds-assistant technique in water. They are water-soluble and highly stable in aqueous solution. CdS QDs evaluated as a luminescence probe for heavy and transition metal (HTM) ions in aqueous solution was systematically studied. Five HTM ions such as silver(I) ion, copper(II) ion, mercury(II) ion, cobalt(II) ion, and nickel(II) ion significantly influence the photophysics of the emission from the functionalized CdS QDs. Experiment results showed that the fluorescence emission from CdS QDs was enhanced significantly by silver ion without any spectral shift, while several other bivalent HTM ions, such as Hg(2+), Cu(2+), Co(2+), and Ni(2+), exhibited effective optical quenching effect on QDs. Moreover, an obvious red-shift of emission band was observed in the quenching of CdS QDs for Hg(2+) and Cu(2+) ions. Under the optimal conditions, the response was linearly proportional to the concentration of Ag(+) ion ranging from 1.25 x 10(-7) to 5.0 x 10(-6)molL(-1) with a detection limit of 2.0 x 10(-8)molL(-1). The concentration dependence of the quenching effect on functionalized QDs for the other four HTM ions could be well described by typical Stern-Volmer equation, with the linear response of CdS QDs emission proportional to the concentration ranging from 1.50 x 10(-8) to 7.50 x 10(-7)molL(-1) for Hg(2+) ion, 3.0 x 10(-7) to 1.0 x 10(-5)molL(-1) for Ni(2+) ion, 4.59 x 10(-8) to 2.295 x 10(-6)molL(-1) for Cu(2+) ion, and 1.20 x 10(-7) to 6.0 x 10(-6)molL(-1) Co(2+) ion, respectively. Based on the distinct optical properties of CdS QDs system with the five HTM ions, and the relatively wide linear range and rapid response to HTM ions, CdS QDs can be developed as a potential identified luminescence probe for familiar HTM ions detection in aqueous solution.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号