基于EDTA的配位滴定通式

根据物料平衡及滴定过程中的体积比,建立了基于EDTA的配位滴定通式,可以计算出EDTA滴定混合金属离子溶液时各种组分的浓度曲线,也可以计算出金属离子指示剂的浓度对滴定曲线的影响,有利于从整体上把握配位滴定过程。此通式还可以导出两种金属离子分别滴定的判据。实际滴定例子的浓度曲线的计算结果表明,本通式与实际情况基本一致。     

配位置换滴定法终点误差公式浅探

当金属离子Ｎ和滴定剂（例如ＥＤＴＡ）的稳定常数Ｋ′（ＮＹ）＜１０８时,不能用ＥＤＴＡ直接滴定Ｎ。若加入过量的另一种配合物ＭＡ于Ｎ的溶液中,发生下列置换反应Ｎ＋ＭＡ＝ＮＡ＋Ｍ（１）若Ｋ′（ＭＹ）比Ｋ′（ＮＹ）大得多,且Ｋ′（ＭＹ）１０８,ＮＡ又足够稳...     

多元线性回归pH配位滴定法同时测定钙和镁

将多元线性回归分析应用于pH配位滴定,提出△lgK_(MY)较小金属离子混合溶液中各组分同时测定的方法,讨论了方法的原理、回归方程和最佳条件.对钙、镁合成样品及实际水样中钙、镁含量进行测定,结果满意.     

非平衡态-恒电位配位滴定法同时测定铁和铝

以氟离子溶液作滴定剂，氟离子选择性电极作指示电极，在氟-铝反应没有达到平衡条件下通过恒电位配位滴定法同时测定了铁和铝。控制溶液的pH值为1．5，温度为25℃，硝酸钠离子强度调节剂浓度为0．1mol／L，反应时间为60s。在氟-铁反应达到平衡，但在氟-铝反应没有达到平衡的条件下，采集滴定数据。根据非平衡条件下，响应值的重现性，利用最小二乘法求出常数kFe、kAl及k0，进而计算出铁和铝的浓度。     

多元线性回归同时PH配位滴定法研究

本文将多元线性回归分析法应用于ＰＨ配位滴定，同时测定了与ＥＤＴＡ综合物稳定常数极为相摈金属离子浓度。讨论了方法原理、回归方程及最佳实验条件。对十个合成样进行了测定，得满意结果。     

配位滴定终点误差的通用计算方法*

依据终点误差的体积比定义式,滴定分析中所加入滴定剂的体积与待测体系的初始体积之比是计算终点误差的关键。建立了配位滴定中关于体积比的一般方程,提出了求解该方程的迭代策略,并给出了终点误差的计算实例。结果表明,该方法具有适应范围广、计算精度高的特点。     

滴定分析的终点误差随待测物浓度及反应平衡常数单调变化之商榷

为了获得滴定分析的终点误差随待测物浓度、反应平衡常数这两个因素变化的准确规律,推导了有别于林邦终点误差公式的终点误差计算式,根据该式可以判断每个因素对计算结果的影响,结合在配位滴定分析和酸碱滴定分析的具体应用,结果发现：这两个因素其大小的变化不会一定导致终点误差绝对值的单调变化。     

恒电位氟-铝配位滴定法测定铝的研究

以氟离子溶液作滴定剂,氟离子选择性电极作指示电极,对恒电位配位滴定法测定铝进行了研究,导出了该测定法的计算模型。测定结果的准确度受电位的控制误差对滴定剂体积误差的影响及滴定剂体积的相对误差两个因素影响。在滴定的中间位置,准确度比较高。随着滴定剂体积的增加,测定的灵敏度增加。方法可用于金属铝及锌一铝合金中铝的测定。     

配位滴定法同时测定混合液中铜,镉

1 引言 本文将多元统计分析法用于配位滴定法中,提出了金属离子混合液中各组分含量同时测定的方法原理和数学模型,根据电位滴定原理,以EDTA为滴定剂,玻璃电极为指示电极,利用多组标准混合液的滴定数据建立校正模型,然后对合成样品中Cu~(2+)、Cd~(2+)两个离子的浓度进行预报。尽管上述二离子间的logK相差较小,勿需分离或掩蔽,仍能得到满意结果,电极系统也不需严格校正。测定原理简述如下:     

配位滴定的离子强度允许范围

用离子强度副反应系数、条件稳定常数和准确滴定的条件推导出配位滴定的离子强度允许范围。     

Complexing and self-complexing of peptide-cavitands

Resorc[4]arene based peptide-cavitands with four identical chiral amino acids at their upper rim were synthesized and investigated for the complexation of small guest molecules. Competition experiments show, that the tetra amino acid cavitands complex small organic guests in chloroform in the order ethyl acetate <dichloromethane < acetonitrile < ethanol < acetamide < acetic acid. The peptide-cavitands containing aspartic and glutamic acid derivatives enclose parts of their attached amino acids in the cavity, so that these peptide-cavitands are host and guest at the same time. The starting material for the cavitands, the resorc[4]arenetetraamine 3, is made by a new synthetic route using the Delépine-reaction.     

Complexing behaviour ofN-phenylcarbamoylpyrrole-2-thiocarboxamide

Summary The complexes Pd(PTH)₂Cl₂ · 3.5 H₂O, Pd(PTH)₃(PPh₃), Ru(PTH)₂(PPh₃)Cl₂, Ru(PTH)₂(PPh₃)Cl₃, Rh(PTH)₂(PPh₃)Cl and Rh(PT)Cl₂ · 0.5 H₂O, where PTH isN-phenylcarbamoylpyrrole-2-thiocarboxamide, have been prepared and characterised by magnetic and spectral (i.r., u.v. and visible) studies.     

Complexing of polyols with cations

Polyols containing three O atoms in a suitable steric arrangement form complexes with cations in aqueous solution. Suitable steric arrangements are (i) three syn-axial oxygen atoms on a 6-membered ring, and (ii) three O atoms on three consecutive C atoms constituting a clockwise and an anti-clockwise gauche arrangement. Complex formation is detected by paper electrophoresis and by NMR spectroscopy. Complex formation with diamagnetic cations causes small downfield shifts in the NMR spectra. Paramagnetic cations cause large shifts which are interpreted as being due to diamagnetic, pseudocontact, and contact interactions. The contact effect appears to be stereospecific: it requires planarity of the resonating nucleus, the metal, and the intervening bonds.     

Differential Complexing by Cyclodextrin Twin-cavity Hosts

The twin-cavity cyclodextrin (1) in which the link is a dithiotrehalosyl unit, and the flexibly-linked dimer (2) were shown to distinguish between the heterocyclic guests 3 and 4 (clofazimine drug) in spite of the guests' small structural difference. Both cyclodextrin dimer hosts form 1:1 complexes with methyl orange and with 3, as shown by double reciprocal plots of UV-absorbance change and host concentration. However with 4, both host molecules formed a 2 : 1 (host : guest) complex . Since both dimer cavities are used to create this effect, it is a new type of selectivity for macrocyclic hosts.     

Acid and Complexing Properties of Tetraazaporphyrins

In this review, the kinetic regularities underlying the formation and stability of acid–base tetraazaporphyrin complexes with nitrogen bases in benzene (chlorobenzene) are considered. The relationships between the structure of protolytes and their reactivities are discussed. The role of the acid–base interactions in the reaction of magnesium acetate or acetylacetonate with tetrahalogen- and octaphenyl-substituted tetraazaporphyrins in the nitrogen-containing base–benzene system was revealed. The possible mechanisms of the processes under study are considered and a relatioship is established between the reaction rate constants and structural changes in a solution.     

Syntheses and Complexing Properties of Polyethers

Diaza-18-crown-6 with two 8-hydroxyquinolines as side arms show high selective complexing ability with metal ions^[1,2] and with two aminophenols exhibit strange property^[3]. 8 diaza-18-crown-6 ethers containing sidearms^[4] and 7 podands were synthesized. Their complexing ability with metal ions were studied, the results show that they present high complexing capability for metal ions. The polyethers containing 8-hydroquinoline fragment show high selectivities for Hg²⁺,Ni²⁺ and their complexes with Eu³⁺ and Tb³⁺ show strong luminescence.