稀土-氨基多羧酸配合物的配位结构及变化规律的研究 II.二乙三胺五乙酸(dtpa)和三乙四胺六乙酸(ttha)系列

在前文的基础上,本文继续综述了氨基多羧酸类-dtpa和ttha配体与一系列稀土金属离子形成配合物的分子结构和配位结构。发现了dtpa和ttha配体与稀土金属离子的配位规律和结构变化规律。研究结果表明,稀土金属离子与dtpa和ttha配体形成配合物的配位数和配位结构明显地取决于稀土金属离子的离子半径,电子结构和氧化态以及配体的形状。     

Investigation of the interaction of Ce(IV) with diethylenetriaminepentaacetic acid

Conclusions The formation of a neutral monocomplex of Ce(IV) with diethylenetriaminepentaacetic acid was found by a spectrophotometric method. The instability constant of the complex at =1.0 and pH 1.4, the value of which was equal to (0.8±0.2)·10^–34, was calculated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2186–2189, October, 1970.     

Interactions of silver with humates and other species in natural waters

Tracer^110mAg has been used to investigate the speciation of silver in natural waters, which may contain chloride, sulphide or humate ions. Silver chloride or oxide is readily absorbed from waters by many materials, and some may be photochemically reduced to metallic silver. Absorbed silver, silver chloride and silver sulphide may be distinguished by their desorption behaviour. Humates form complexes with silver chloride, silver sulphide and the silver cation, which can be separated from smaller species by gel permeation chromatography.     

三乙四胺六乙酸钆配合物的合成及晶体结构

在水溶液中合成了三乙四胺六乙酸钆配合物:K4[Gd2(HTTHA)2].14H2O的单晶, 并测定了其结构。晶体属单斜晶系, P21/n空间群。晶胞参数: a=1.1266(5)nm,b=2.5686(4)nm, c=2.2076(8)nm, β=102.50(3)°,V=6.237(6)nm^3, Z=4, Dc=1.812g/cm^3。配合物是比核分子,每个钆离子与来自同一个三乙四胺六乙酸的3个氮原子和4个羧基氧原子, 来自另一个三乙四胺六乙酸的2个羧基氧原子配位,形成三冠三角棱柱型配位多面体。     

DNA cleavage promoted by diethylenetriaminepentaacetic acid （DTPA） derivatives

DTPA and its two derivatives were synthesized and used as catalysts in DNA cleavage.Under physiological conditions,a series of experiments have been done.The effects of DNA cleavage with three ligands were studied under different concentrations, cleavage time,and pH values.The results strongly suggested that the plasmid DNA(pUC 19) can be cleaved efficiently by CITC-DTPA. For the cleavage reaction catalyzed by CITC-DTPA,FormⅠDNA could convert to FormⅡmostly,and the DNA-cleavage mechanism involved an oxid...     

The stability constants of some metal chelates of triethylenetetraminehexaacetic acid (ttha)

Stability constants for Al(III), Cd(II), Co(II), Cu(II), Fe(III), Hg(II), La(III), Nd(III), Er(III), Mg(II). Mn(II), Ni(II), Pb(II), Th(IV) and Zn(II) complexes of triethylenetetraminehexaacetic acid (TTHA) have been evaluated from data obtained by pH and pM measurements. The pM method based on measurements with the mercury electrode and the redox system Fe(III)/Fe(II) proved to be very useful when binuclear complexes are formed.     

Analysis of nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) in water, particularly waste water

Summary Two chromatographic techniques can be considered for the detection of the complexing agents NTA, EDTA and DTPA in water: gas chromatography (GC) and liquid chromatography (HPLC). GC is capable of detecting all three compounds in concentrations of as little as 0.001 mg/l. However, this requires a complex and time-consuming sample preparation (enrichment, derivatization). HPLC represents a possible alternative for detecting EDTA and DTPA. Without enrichment it is possible to reach a detection limit of 0.1 mg/l, i.e., while this method is rather less sensitive, it provides results in a much shorter time. If the sample concentrations are high enough, this method is more suitable for conducting routine monitoring of emissions of EDTA and DTPA in waste water. Simple matrices such as surface water or drinking water can be enriched on a pre-column to reduce the detection limit.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Synthesis and relaxivity of Gd(III), Fe(III) and Mn(II) complexes with dihydropyridine derivative of diethylenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T₁) were investigated. The results show that the NMR T₁ relaxivitives (R₁) for complexes of Fe(III), Mn(II) are less than that of Gd(III) complex, which has a high relaxivity (R₁) on the surrounding water protons, indicating that the Gd(III) complex possesses the precondition to be contrast agents for magnetic resonance imaging.     

Phenolic aldehydes and aldoximes as indicators for direct titration of ferric ions with diethylenetriaminepentaacetic acid (DTPA)

Summary Fifteen phenolic aldehydes and aldoximes have been investigated as indicators for the direct titration of iron(III) ions with diethylene triaminepentaacetic acid. Six substances are found to be excellent indicators which permit direct titration of iron(III) with DTPA even at pH 1.0. Microtitrations are feasible with these indicators, the minimum titratable amount being 56g/ml. The process is very selective and can be applied to the analysis of ores and drugs containing iron.

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Pbenolische Aldehyde und deren Oxime als Indikatoren für die direkte Titration von Eisen(III) mit Diethylentriaminpentaessigsäure (DTPA)

Zusammenfassung Sechs phenolische Aldehyde bzw. deren Oxime bewährten sich als ausgezeichnete Indikatoren für die direkte Titration von Eisen (III) mit DTPA bei pH 1,0. Die geringste titrierbare Menge beträgt 56g/ml. Die Reaktion ist sehr selektiv und eignet sich für die Analyse von Erzen und eisenhältigen Drogen.

     

Synthesis and relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ)complexes with dihydropyridine derivative of diethylenetriaminepentaacetic acid

A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging.     

Potentiometric determination of Ca(II), Nd(III) and Pu(III) chelates formed by diethylenetriaminepentaacetic acid

A method for direct analysis of the curves of potentiometric (pH) measurements of equimolar M^z++H_nL chelating systems has been worked out. It is based on the balance of ionic charges and the mass balances of metal ion, ligand and hydrogen. The results of the study of Ca(II), Nd(III) and Pu(III) chelates with DTPA are given.     

Spectrophotometric determination of silicate in natural waters by formation of α-molybdosilicic acid and reduction with a tin(IV)-ascorbic acid-oxalic acid mixture

Reaction of dissolved silicate with molybdate at pH 3.8–4.8 in acetate buffer yields only the α-molybdosilicic acid. Treatment of this acid with a solution containing tin(IV) chloride, ascorbic acid and oxalic acid rapidly gives the blue reduced acid without reducing the excess of molybdate reagent. In the recommended procedure, Beer's Law is followed at 740 nm over the range 0–2000 μg Si l^-1 with a coefficient of variation of 0.34% at 400 μg Si l^-1 and 0.52% at 40 μg Si l^-1. The sensitivity of the method is not affected by ionic strength.     

Trace determination of α-keto acid in natural waters

Numerous chromatographic methods have been developed to detect α-keto acids in physiological or sea-water samples. These methods generally involve derivatization in a strongly acidic medium with elevated temperatures, desalting, preconcentration, and liquid-liquid extraction procedures prior to chromatographic analysis. These procedures may introduce significant errors because of adsorption losses, contamination, or decomposition of the α-keto acids. To avoid these potential problems, a chemically mild method to detect α-keto acids in sea water was developed. The method is based on the reaction of α-keto acids with 2,4-dinitrophenylhydrazine in sea water to form stable hydrazone derivatives. Desalting of the reaction mixture and preconcentration of the hydrazone derivatives is accomplished by a column-switching technique. The derivatives are separated by reversed-phase, high-performance liquid chromatography and detected by absorption spectrometry. Quantification of α-keto acids in the nM to μM concentration range shows complete recovery in sea water, excellent precision at 10–20 pmol (<5% relative standard deviation), and absorbances that are linearly related to α-keto acid concentrations. The detection limit of this method is 1–5 pmol for a 2-ml injection. Applications of this method to the detection of α-keto acids in marine sediment and sea-water samples are illustrated, and the first shipboard results are presented.     

Structural study of bismuth complexes with diethylenetriaminepentaacetic acid in aqueous solutions

Bismuth complexes with diethylenetriaminepentaacetic acid were examined in aqueous solutions (pH 4–10) by UV, IR, and NMR spectroscopy. In aqueous solutions, the polydentate ligand is coordinated to bismuth through three N atoms and five O atoms.     

Trace analysis of aluminum in natural waters with rubeanic acid by adsorption chronopotentiometry

The determination of trace levels of aluminum in natural waters with rubeanic acid (RA) by adsorption chronopotentiometry is developed in this paper. Optimum experimental conditions include an accumulation potential of -0.40 V, accumulation time of 60 s, and a RA concentration of 6x10(-6) M in 0.2 M NaAc-HAc buffer solution (pH 4.6). The response is linear over the 1x10(-8) approximately 4x10(-7) M concentration range. The detection limit is 5.6x10(-9) M and the relative S.D. (at the 3x10(-7) M level) is 2.6%. Possible interferences are evaluated. The method has been applied to the determination of trace levels of Al in various real samples. Direct determination of toxic forms of Al in surface waters by this technique is also explored.     

Preconcentration of lanthanides from natural waters with a lipophilic crown ether carboxylic acid

Lipophilic crown ether carboxylic acids such as 2-(sym-dibenzo-16-crown-5-oxy)stearic acid with a cavity size comparable to the ionic radius of rare-earth elements are selective chelation agents for preconcentration and separation of lanthanides from natural waters for NAA. Interfering matrix elements such as sodium and bromine can be simultaneously eliminated during the extraction. The lanthanides can be back-extracted into a dilute acid solution for NAA, thus providing a large preconcentration factor. This two-step extraction method appears suitable for the determination of lanthanides in natural waters and in biological samples.     

Simulataneous substoichiometric determination of europium and terbium with diethylenetriaminepentaacetic acid and 2-thenoyltrifluoroacetone

The simultaneous substoichiometric separation of europium and terbium is presented and its application to the determination of these elements with DTPA and HTTA is developed. Experimental results for the simultaneous substoichiometric separation are in good agreement with the theoretical results introduced by the principle. Europium and terbium in orchard leaves are determined by simultaneous substoichiometric neutron activation. The analytical values are 23±1.1 ppb for europium, and 17±1.2 ppb for terbium.