电位法和极谱法联合确定镉-甘胺酸络合物稳定常数

The cadmium(Ⅱ)-glycine system was studied by the two experimental techniques, ion sensitive electrode (ISE) and differential pulse polarography (DPP), and the experimental data obtained were used by a unified mathematical treatment to calculate the complex stability constants. The combination of the two techniques is of many advantages as ISE can be performed at low LT:MT ratios and significantly higher MT, whereas DPP could be used well at large LT:MT ratios and much smaller MT. This makes it possible to study a metal-ligand system in a relatively broader range of experimental conditions that, in turn, provides more information about the metakligand system of interest. Applying the unified mathematical treatment to the cadmium-glycine system, two new complexes MHL and ML2(OH) as well as three complexes ML, ML2 and ML3, reported in literatures, could be modeled and all their stability constants have been refined.     

示差脉冲极谱法确定镉(Ⅱ)-甘胺酸体系的配合物稳定常数

在镉离子浓度为5.00×10-5~2.00×10-4mol.L-1、甘氨酸与镉离子浓度比为100~400条件下,应用示差脉冲极谱技术测定不同溶液pH值时镉(Ⅱ)-甘氨酸体系的极谱峰电位和峰电流,依据极谱峰电位随溶液pH和自由金属离子浓度的变化关系曲线,建立合适的金属配合物体系模型。通过求解体系的质量平衡方程及拟合试验配合物形成曲线,用计算机分析程序优化得到MHL、ML、ML2、ML3和ML2(OH)五种金属配合物的稳定常数(lgβ)分别为9.67±0.15,4.35±0.02,7.83±0.03,10.04±0.04和11.48±0.13。     

极谱配位吸附波测定配合物表观稳定常数的方法研究

对目前利用配位吸附波测定配合物表观稳定常数的常用方法进行了修正,提出了更具有普遍适用性的测定配合物表观稳定常数的理论公式,并对计算方法进行了探讨,获得了预期的满意的结果。     

不足量配位剂存在时铜(Ⅱ)-乙二胺体系的极谱行为及其稳定常数的测定

本文继前文的工作,探讨在不足量配位剂存在时配合物的极谱行为以及同时测定各级配合物稳定常数的可能性。 1 实验部分     

磺基水杨酸金属配合物稳定常数实验值的讨论

在目前无机(普通)化学基础实验中,几乎各个学校都作了磺基水杨酸铁(或铜)配合物的组成和稳定常数的测定。有的学生和老师将稳定常数测定值与文献值相对照,发现相差好几个数量级,因此对自己的实验值产生了怀疑。不少学生和老师对磺基水杨酸金属配合物的表观稳定常数和热力学稳定     

氨基乙酸金属配合物稳定常数测定实验的改进

通过改用自动电位滴定仪在氮气保护和恒温条件下准确地对氨基乙酸-硝酸铜体系进行滴定和数据拟合,正确掌握有机酸碱离解常数和金属配合物稳定常数测定的科学方法。     

平衡移动法测定配合物组成和稳定常数的研究进展

平衡移动法是测定配合物组成和稳定常数的一种重要方法，本文综述了该法的研究进展，引用参考文献３０篇。     

图解法测定多核配合物组成和稳定常数

配位化合物中不少先前被认为是简单的１∶１配合物，而实际上却是多核配合物，原因是它们的组成比相同，都是１，因而多核配合物的存在不易被发现目前已有数种方法可以识别并可测定其稳定常数，如图解偿试法，但计算较繁琐本文基于直接测定配合物吸光度建立一种新的图解法，不需通过偿试而后测定多核配合物组成和稳定常数，实验与计算均较简单，试用于Ｆｅ（Ⅲ）ＥＣＲ或ＣＡＳ体系，获得了满意的结果     

钕(Ⅲ)—泛酸配合物稳定常数的吸收光谱法测定

电位法测定了DL-泛酸的离解常数.利用Nd~(3+)离子超灵敏跃迁(~4I_(9/2)→~2,4G_(7/2,5/2)的振子强度伴随配体浓度的变化,确定了水溶液中钕(Ⅲ)—泛酸配合物的累积稳定常数lgβ_i分别为2.01,3.87,5.60.     

柱上衍生反相色谱法测定金属配合物的稳定常数

提出一种计算金属配合物稳定常数的新方法。应用住上衍生反相高效液相色谱法,以二乙基二硫代氨基甲酸钠为配体,测定金属配合物的保留时间,用以推导金属配合物的稳定常数。     

利用络合物形成曲线设计金属络合物体系模型及优化络合物稳定常数

In this paper the Bi(Ⅲ)-ligand(pyridine-2-carboxylic acid) system was studied by direct current sampled polarography (DC_TAST) at a fixed ratio of total-ligand to total-metal concentration and changing pH. The po-larographic experimental complex formation curve (ECFC) and the theoretical complex formation curve (TCFC) were used for modelling the metal-ligand system and optimizing stability constants. The ECFC， in which experi-mental parameters of polarography are included (a shift in a half-wave potential and a variation in a diffusion controlled limiting current)， appears to be a characteristic function for a particular metal-ligand system. The TCFC is a theoretical curve calculated for the designed metal-ligand model from mass-balance equation. Five bismuth complexes MHL， ML， ML₂， ML₃ and ML₃(OH) with their stability constants as logβ 7.54±0.10， 7.50±0.02， 13.91±0.04， 18.15±0.03 and 26.75±0.02， respectively， are reported.     

络合物形成曲线用于金属络合物稳定常数的极谱法研究

本文用示差脉冲极谱技术研究Pb(Ⅱ) 络合剂(β N 三丙酸)体系。依据实验得到的极谱峰电位的移动随溶液pH值的变化关系曲线,建立合适的金属络合物体系模型。用计算机分析程序,通过求解体系的质量平衡方程及拟合实验络合物形成曲线,优化得到金属络合物的稳定常数。计算机分析结果表明,在所研究的pH值范围内,溶液中存在四种金属络合物:PbH2L+、PbHL、PbL-、PbL(OH)2-,其稳定常数(logβ)分别为:16.23±0.04、12.42±0.01、4.11±0.05、9.43±0.02。     

Potentiometric and Thermogravimetric Studies on Some Metal–Oxine–Sulphadrugs ternary Complexes

Formation constants (logK _MAL ^MA) of the mixed complexes of the type M–A–L (where M=Mn(II), Co(II), Ni(II), Cu(II), Ce(III), Th(IV), and UO₂(II); A=oxine and L=sulphamerazine or sulphadiazine) have been determined pH-metrically in 60% (v/v) ethanol–water mixture at 25°C and constant ionic strength (μ=0.1 M NaCl). The mode of chelation was ascertained by conductivity measurements. The stability sequence with respect to metal ions have been found to be Cu(II)>Ni(II)>Co(II)>Mn(II) and Th(IV)>UO₂(II)>Ce(III). CuAL ternary solid complexes have been prepared and characterized on the basis of elemental analysis and IR-spectroscopy. The thermal degradations of the prepared complexes are discussed in an attempt to assign the intermediate compounds formed. This revised version was published online in August 2006 with corrections to the Cover Date.     

主-客体络合物稳定常数的曲线拟合处理

利用曲线拟合法以处理圆二色谱法谱滴定的实验数据,可以给出更为可靠的主－客休络合物的络合稳定常数,与常用的Ｂｅｎｅｓｊ－Ｈｉｌｄｅｂｒａｎｄ方程所得结果比较表明,当络合物稳定常数较大（〉５０００）时,应该使用曲线拟合法。     

线性扫描伏安法测定铅-L-谷氨酸络合物稳定常数

本文介绍了用线性扫描伏安法以玻碳电极为工作电极测定铅-L-谷氨酸络合物的稳定常数,研究了支持电解质及酸度的影响,在最佳实验条件下,获得了络合物的配位数和累积稳定常数。方法简便,快速准确,有实际意义。     

Polarographic Behaviour and Determination of Stability Constants of Uranyl-Ascorbate Complex

The complex species of UO₂(HA)(H₂A)⁺ and UO₂(HA)₂ were identified in the ascorbic acid solution of uranyl ion at pH<2.1 and pH>2.1, respectively. Polarographic wave was proved to be the simultaneous reduction of UO₂⁺² and UO₂(HA)(H₂A)⁺ at pH <2.1. However, at pH>2.1, the wave is due to the reduction of U0₂(HA)₂ The stability constants of the two complex species were found to be 5.1×10⁺ and 1.0×10⁵, respectively. The hydrolysis constant of uranyl ion in the solution of ascorbic acid was determined.     

分光光度法测定络合物稳定常数及摩尔吸光系数的通用算法

提出了一个用单纯形法与线性最小二乘法结合的方法计算络合物稳定的常数及摩尔吸光系 的新算法,并处理了Ｃｊ＾２＋－ＰＡＮ－Ｓ络合体系的数据,求得了该络合物的第一,二级稳定常数。