Complexes of Di‐ and Triazacrown Ethers with Heavy Metal Ions in Water Solution

This research concerns the analysis of the metal ion binding of benzo‐ and pyridine‐azacrown ether compounds of different structures and sizes by potentiometric method. The ligands are able to form 1 : 1 complexes with heavy metal ions (Cu⁺², Pb⁺², Cd⁺², Ag⁺, Ni⁺², Zn⁺²) in water of middle or high stability. To understand the selectivity in cation binding, different factors were considered.     

水中重金属离子电富集样品处理技术

提出了一种低浓度重金属离子溶液的快速富集净化处理方法。目标金属离子首先络合为负离子,在正电压牵引下,金属络合离子到达离子膜表面,在膜表面阴离子层吸引下通过阳离子交换膜,并在受体溶液中再次络合为阴离子络合物,在电场作用下向阳极区移动。富集电流为1.5mA,汞离子、镉离子的富集时间分别为20,60min,水样中汞离子、镉离子的富集倍数分别为10.5,3.2倍。本方法避免了液膜稳定性缺陷。     

冠醚聚合物的研究 Ⅱ.以聚硫醚为主链的硫杂冠醚聚合物的合成及其络合性能

本文报道了一种合成硫杂冠醚聚合物的新方法。以聚(2′-氯乙基-2,3-环硫丙基醚)为预聚物与二巯基化合物通过大分子反应直接环化,一步法合成了四种以聚硫醚为主链的新型硫杂冠醚聚合物(PD1-PD4)。并测定了它们对Ag~+、Au~(3+)、Pd~(2+)、Pt~(4+)、Cu~(2+)、Hg~(2+)、Zn~(2+)、Cd~(2+)、Pb~(2+)、Mg~(2+)、K~+、Ns~+等金属离子的络合性能。结果表明:它们除不络合K~+、Na~+、Mg~(2+)、Pb~(2+)外,对其它八种离子有不同程度的络合,其中对Ag~+、Au~(3+)、Pd~(2+)等贵金属离子的络合容量较高。     

Complexation of Metal Ions with Azacrown Ethers Bearing an 8-Hydroxyquinoline Side Arm

Thermodynamic quantities (log, K, H, and TS) for theinteractions of six azacrown ethers each bearing an 8-hydroxyquinoline (CHQ)side arm (1-6) with Na+, K+, Ba2+, and Cu2+ were determined by calorimetrictitration in methanol solution at 25°C. The results indicate that theseligands form stable complexes with the cations studied. Ligands 1 and 3 thathave CHQ attached through position 7 (next to the OH group) show highselectivity for Cu2+ (log K values of 8.12 and 9.44, respectively) over Na+,K+, and Ba2+ by more than four orders of magnitude. On the other hand,ligands 2 and 4 that have CHQ attached through position 2 (next to thequinoline nitrogen group) form more stable complexes with Na+, K+, and Ba2+,but less stable complexes with Cu2+, than ligands 1 and 3. All ligandsinteract more strongly with K+ than with Na+. The K+/Na+ selectivity forligands 4 and 5 is about 1.5 log K units. All complexation reactions displaynegative enthalpy changes. In most cases the entropy changes are alsonegative, indicating that formation of the complexes is enthalpy driven. 1HNMR spectral experiments demonstrate coordination of the cations by alldonor atoms of the ligands including those of the CHQ arm. In all cases, theOH signal is observed in the 1H NMR spectra, suggesting that thecomplexation with the cations does not involve deprotonation of the CHQgroups in the ligands.     

Tetra(diethyl)amide-p-tert-butyl-thiacalix[4]arene in Cone Conformation: Synthesis and Binding Properties with Alkali,Alkaline Earth,Heavy and Transition Metal Ions

Tetra(diethyl)amide-p-tert-butylthiacalix[4]arene 1a in the cone conformation was synthesized and its binding properties towards a large variety of metal ions were established on the basis of liquid–liquid and solid–liquid extraction as well as complexation experiments. This compound is a less efficient and selective compound than the “classical” tetra(diethyl)amide-p-tert-butylcalix[4]arene 3 in the cone conformation for alkali and alkaline earth metal ions. However, Pb²⁺ is selectively extracted and complexed within heavy and transition metal ions.     

重金属离子富集检测的微量热研究

采用微量热技术对重金属离子的富集检测过程进行了研究. 采用流动注射分析法研究了重金属离子进样顺序、 样品进样流速和载体树脂颗粒粒径对重金属离子抑制脲酶催化反应的影响, 优化了脲酶及重金属离子进样量, 获得了脲酶固定化及重金属离子富集条件的优化参数. 结果表明, 在低流速(0.1 mL/min), 载体树脂颗粒粒径为0.5～0.6 mm, 脲酶进样量为3 mL, 重金属离子进样量为5 mL的条件下, 先进行重金属离子的富集, 再检测其对固定化脲酶催化反应的影响可得到较好的检测效果. 在实验浓度范围内, 4种重金属离子对脲酶催化反应的影响顺序为砷离子>铜离子>镉离子>铅离子. 本文对重金属离子进行了适当的富集, 降低其检测下限, 为采用微量热法进行重金属离子的快速检测提供了理论依据.     

Factors Influence Complexing Selectivity of Lariat Crown Ethers Toward Alkali Metal Ions in Electrospray Ionization Mass Spectrometry

The selectivity of eight lariat crown ethers in the sym‐dibenzo‐16‐crown‐5 series toward alkali metal ions was studied with electrospray ionization mass spectrometry under different conditions. With the exception of 2g , which is equally selective toward Na⁺ and Li⁺, all other lariat crown ethers show the best selectivity toward Li⁺ in methanol. Factors that influence the selectivity include the water content, counterions, nature of the side arms, and the externally added cations. Iodide gives the best Na⁺ selectivity with R_I > R_Br > R_Cl. Increased water content profoundly increases the Na⁺ selectivity when the side arm is hydrophilic and the steric hindrance is small. Externally added cations (Cs⁺ and/or Rb⁺) enhance the Na⁺ selectivity by exchanging the smaller Li⁺ from the cavity.     

Synthesis and Complexing Properties of Novel Crown Ethers and Thiacrown Ethers Incorporating New Heterocyclic Moieties

The synthesis of some novel crown and thiacrown ethers via the reaction of 2,3-bis(4-hydroxyphenyl) or 2,3-bis(4-mercaptophenyl)quinoxalines and pyridopyridazine with diethylene and triethylene glycol ditosylate is described. The complexing ability of compounds 5b and 5h, as the representatives of both groups of compounds, with alkali and alkali earth metal cations were measured by the solvent extraction method. The results showed that crown ether 5b comparatively had more affinity towards the Mg²⁺ cation, while thiacrown ether 5h had greater affinity towards the Ca²⁺ cation.     

Diamino‐Substituted Carbene Transfer between Transition Metal Ions

Diamino‐carbene ligand transfer between various metalions is studied, particularly with Pd (II) to Rh(I), Rh(I) to Au(I). Reactions of various carbene complexes with AgPF₆ result in the cleavage of the M=C bond to give the protonated carbene species, imidazolidin‐2‐ylidinium salt, indicating the presence of free carbene ligand in the reaction medium. When the carbene transfer process was carried out in tetrahydrofuran, the polymerization of tetrahydrofuran occurred.     

冠醚苯酚共缩聚物的合成与性能

由２，６－二羟甲基－４－甲基（或磺酸基）苯酚分别和芳香族冠醚（Ｂ１５Ｃ５、Ｂ１８Ｃ６、ＤＢ１８Ｃ６、ＤＢ２４ｃ８等）在强酸催化剂下缩聚，合成了２个系列冠醚共缩聚物。它们的萃取能力和配合作用均优于相应的单冠醚，并可作为树脂吸附分离多种金属离子，作为配合剂测定钾、钠以及作为气相色谱固定液分离多种有机物。     

水杨酸型螯合吸附材料对重金属离子的吸附性能

将5-氨基水杨酸接枝到PGMA/SiO2微粒的聚甲基丙烯酸缩水甘油酯(PGMA)大分子链上,成功制备了一种新型螯合吸附材料ASA-PGMA/SiO2。采用静态法研究了ASA-PGMA/SiO2对重金属离子Cu2+、Cd2+、Zn2+、Pb2+的吸附性能,结果表明其对Cu2+、Cd2+、Zn2+、Pb2+具有很强的螯合吸附能力,吸附容量分别可以达到0.42、0.40、0.35、0.31mmol/g。体系的pH对吸附容量影响较大,吸附行为服从Langmuir和Freundlich吸附模型。使用0.1mol/L的盐酸溶液就可实现重金属离子的解吸。通过反复吸附-解吸实验证明ASA-PGMA/SiO2具有良好的重复使用性能。     

Inhibitive Determination of Heavy Metal Ions by Conductometric Nitrate Reductase Biosensor

A conductometric nitrate biosensor based on methyl viologen/Nafion/nitrate reductase(NR) interdigitated electrode for heavy metal determination was proposed.The activity of NR(EC 1.6.6.2) from Asper gillusniger(A.niger) was assayed as a function of metal concentration in the presence of Cu2+,Zn2+,Cd2+ and Pb2+.Parameters influencing the performance of the biosensor were optimized for the application of it in the inhibition determination of heavy metal ions.Detection limits for Cu2+,Zn2+,Cd2+ and Pb2+ were ...     

The Preorganization Effect of the Calix[4]arene Platform on the Extraction Properties of Acetylhydrazide Groups with Transition Metal Ions

The binding properties of the cone conformer of O,O,O,O-tetrakis[hydrazinocarbonylmethyl]-4-tert-butylcalix[4]arene, the cone and the 1,3-alternate conformers of the corresponding thia analogue have been evaluated by means of liquid–liquid extraction for a large variety of metal ions. The extraction constants and the stoichiometries of the complexes formed have been determined. Comparison of the extraction properties of calix[4]arenes with their acyclic monomeric analogue clearly demonstrated, that the preorganization of acetylhydrazide groups on the calix[4]arene platform is the cause for a significant improvement of its binding properties. The presence of additional “soft” nitrogen binding sites in acetylhydrazide derivatives of calix[4]arenes compared to their amide derivatives leads to a shift from their classical selectivity for alkali and alkaline earth cations to transition metals. The cone conformer of tetrathiacalix[4]arene shows higher selectivity in a series of d-metal ions compared with its “classical” analogue. The 1,3-alternate conformer exhibits an excellent extraction selectivity for Cu²⁺ and Hg²⁺.     

金纳米粒子在重金属离子检测方面的应用研究

近年来,贵金属纳米材料由于其具有独特的光学性质、稳定性、生物相容性和自身的结构特性等优点,被广泛用于重金属检测领域。总结了近年来金纳米粒子在重金属离子检测方面的研究现状,最后对贵金属纳米材料在重金属离子检测中的发展前景进行了展望。     

金纳米粒子在重金属离子检测方面的应用研究

近年来,贵金属纳米材料由于其具有独特的光学性质、稳定性、生物相容性和自身的结构特性等优点,被广泛用于重金属检测领域。总结了近年来金纳米粒子在重金属离子检测方面的研究现状,最后对贵金属纳米材料在重金属离子检测中的发展前景进行了展望。     

水体中重金属离子的检测方法研究进展

对应用于水体中重金属离子含量的检测方法如络合滴定法、分光光度法、化学发光法、电化学分析法、色谱法、光谱法和质谱法等得现状(主要在1985～2010年间发表的文献)及相关的原理和方法的特点作了综述(引用文献共61篇)。     

杯[4]冠醚对过渡金属离子的液膜传输行为

藉杯芳烃衍生物的识别作用可以实现对金属离子的选择性液膜传输,本文研究了4种新型杯[4]冠醚对5种过渡金属离子（Cu^2 ,Fe^3 ,Co^2 ,Ni^2 ,Zn^2 ）的液膜传输行为,发现其中酯型杯[4]冠醚（Ⅲ）对Cu^2 有优良的传输效能,并考察考察了各种因素（包括源相和受相酸度、离子载休Ⅲ的浓度、时间及温度等）的影响,指出载体Ⅲ对C ^2 的传输为H^ 交换机理,并对该过程进行了初步解释。     

基于表面增强拉曼光谱的重金属离子检测

以对巯基苯甲酸为拉曼标记和自组装修饰分子, 在光亮金基底上修饰后作为检测基底, 在金纳米粒子表面修饰后获得具有表面增强拉曼光谱信号的标记金溶胶. 修饰的基底及纳米离子通过重金属离子与羧基端的配位而发生相互作用, 最终形成“金属基底-对巯基苯甲酸/重金属离子/对巯基苯甲酸-金属纳米颗粒”的三明治结构. 采用扫描电镜表征纳米粒子的组装及以表面增强拉曼光谱检测表面标记分子的信号, 以此实现重金属离子的检测. 以强螯合剂EDTA溶液淋洗三明治结构, 使重金属离子与金属基底以及纳米颗粒上的羧基的配位作用断裂, 获得可再次利用的修饰金基底.     

基于Android平台的便携式痕量重金属离子检测仪的研制

基于Android平台,设计了一种用于痕量重金属离子检测的便携式电化学分析检测仪。仪器输出电压范围为-3~3 V,精度为0.1%,分辨率<1 mV;电流检测范围为-10~10 mA,精度为0.1%,最小分辨率为10 pA,已达到普通电化学分析的要求。借助Android智能设备在人机交互方面的优势,仪器设有专业检测模式与快速检测模式,简化了复杂的电化学检测分析过程,可同时满足专业用户与普通用户的操作需求。使用本仪器,并结合商品化的电极对Cu, Cd, Pb及Hg等常见的重金属离子进行了初步检测,线性范围、重复性及结果准确度方面都获得了满意的结果。     

识别过渡金属离子的1,8-萘二甲酰亚胺多胺衍生物荧光传感器的研究

A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the e±cient intramolecular photoinduced electron transfer (PET). However, after addition of the transition metal ions, the chemosensor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn2+ and Cd2+. The fluorescent chemosensors with different polyamine as receptors show diverse a±nity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission.