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1.
Stability Constants of Complexes of Divalent and Rare Earth Metals with Substituted Salicynals 总被引:1,自引:0,他引:1
Summary. 5-Chloro-4-6-dimethyl-salicylaldehyde was synthesized from 4-chloro-3,5-dimethyl-phenol. A series of substituted salicynals
were obtained by condensation of 5-chloro-4,6-dimethyl-salicylaldehyde with several amines. The amines were chosen such as
to vary the basicity of salicynals by changing the substituents at one of the coordination sites. The stability constants
of complexes of bivalent (Mg2+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+) and trivalent (Y3+, La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Er3+, Yb3+) metal ions with these salicynals and the pK values corresponding to the dissociation of the phenolic proton and the association of a proton to the azomethine nitrogen
were determined potentiometrically using the Calvin-Bjerrum technique as adopted by Irving and Rossotti at 303 K and a constant ionic strength of 0.1 M in a 75:25 (v/v) dioxan-water mixture in an inert atmosphere. The influence of substituents on the proton affinity of the
ligands was examined on the basis of inductive and mesomeric effects. It is also shown that some of the complexes possess
antibacterial, antitubercular, antifungal, and anticoagulant activity.
Received August 5, 1999./Accepted November 11, 1999 相似文献
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Diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) is an octadentate aminopolycarboxylate complexing agent whose f-element complexes find important practical applications in nuclear medicine and in advanced nuclear fuel reprocessing. This investigation focuses primarily on the latter application, specifically on characterization of lanthanide–DTPA complexes of relevance to the Trivalent Actinide–Lanthanide Separations by Phosphorus reagent Extraction and Aqueous Komplexants (TALSPEAK) process. To function acceptably, the TALSPEAK process requires the presence of moderate concentrations (0.5–2.0 mol·L?1) of a (Na+/H+) lactate (or citrate) buffer. Competition between DTPA, lactate, and the extractant bis(2-ethylhexyl)phosphoric acid (HDEHP) for the lanthanides and trivalent actinides governs the course of the extraction process. To facilitate modeling and to support process improvements, the acid dissociation constants and stability constants for rare earth complexes with DTPA have been determined in 2.0 mol·L?1 ionic strength (NaClO4) media. The acid dissociation constants for DTPA and the stability constant for [Eu(DTPA)]2? also were determined in sodium trifluoromethanesulfonate at 2.0 mol·L?1 ionic strength to evaluate the potential impact of changing the nature of the electrolyte. The thermodynamic data are compared with earlier reports of similar data at lower ionic strength and used to complete calculations exploring the relative stability of lanthanide–DTPA and lactate complexes under TALSPEAK extraction conditions. Lanthanide–DTPA stability trends are discussed in comparison with literature data on a variety of other metal ions. 相似文献
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The Polarographic behaviour of quinaldic acid in the presence of lanthanide cations (Kd3+, Gd3+, Er3+) is studied at pH=4.5 and 0.1 M HClO4 as supporting electrolyte. The polarographic reduction gives two waves at lower concentrations of quinaldic acid and three waves at higher concentrations. The nature of the waves was investigated. The dissociation constant of quinaldic acid as well as the stability constants of some lanthanide cation complexes with quinaldic acid were determined potentiometrically in 75% (v/v) dioxane-water at 25°C and 0.1 M KNO3. The solid complexes of Nd, Gd and Er were isolated and studied by ir, differential thermal analysis (DTA) and thermogravimetric analysis (TGA) techniques. 相似文献
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The dissociation constants of m-, and p-phenylenediaminetetraacetic acid (m-, and p-, PDTA) have been determined potentiometrically at room temperature (about 25°C) in an ionic strength of 0.10 M KNO3. The stability constatns of their metal complexes have also been determined by UV spectroscopic, potentiometric, and polarographic methods. The formula of the metal complexes by spectroscopic and polarographic methods are both in good agreement to be 1:1. The order of the stability of the metal complexes is: Cu>Ni>Zn>Co>Cd>Mg, Ca, Ba, Sr. Which is in accordance with Irving-William stability order. 相似文献
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Guo Qiang SHANGGUAN* Jun ZHU Ke Ying WANG Arthur E. MARTELL Department of Chemistry Jining Medical College Jining Department of Chemistry Texas A&M University College Station Texas 《中国化学快报》2001,(10)
The study on the design and synthesis of model compounds for metalloproteins has been a subject of extensive investigation1. During the last decade, a number of synthetic structural models for some kinds of metalloproteins with several types of ligands have been reported in literature2,3,4. We have recently reported a new 24-membered hexaazadiphenol macrocyclic ligand, 3,6,9,17,20,23-hexaaza-29,30-dihydroxy-13,27-dimethyl-tricyclo [23,3,1,111,15] triaconta-1 (28),11,13,15 (30),25,26-hexaene,… 相似文献
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The dissociation constants of carminic acid (7-D-glucopyronosyl-3,5,6,8-tetra- hydroxy-1-methyl-9,10-dioxo-anthracene-2-carboxylic acid) (CA), together with the stability constants of its Cu(II), Zn(II), Ni(II), Co(II) and Hg(II) complexes, were studied potentiometrically in aqueous medium at 25.0?(1)?°C, and at the ionic background of 0.1?mol?dm?3 of NaCl, and determined with the SUPERQUAD computer program. It has been observed that carminic acid has five dissociation constants, and for H5L their values are 3.39?(7), 5.78?(7), 8.35?(7), 10.27?(7), and 11.51?(7). This ligand behaves as a bi-dentate ligand, and the carboxyl and the ortho hydroxy groups of the ligand coordinate to the metal ions. Various metal complexes were produced in solution under the experimental conditions, for each metal ion used, including hydrolyzed species. The species distribution curves of the complexes formed in the solution were calculated and reviewed. The stability of the complexes was found to follow the order: Cu(II) > Zn(II) > Ni(II) > Co(II) > Hg(II). 相似文献
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二价稀土(Sm,Eu,Yb)与3-苯基-5-(呋喃-2)吡唑啉二硫代甲酸固态配合物的制备 总被引:1,自引:0,他引:1
本文首次制得了二价稀土与含硫有机配体的固态配合物RE(SSCNC13H11NO)2·xH2O(RE=Sm,Eu,Yb,x=3,4),研究了它们的性质,并对二价及相应的三价稀土配合物在物理化学性质上的差异进行了探讨。 相似文献
10.
The metal ligand stability constants of violuric acid [H2VA], N-methyl violuric acid [H2MVA], N-phenyl violuric acid [H2PVA] and N-(o-m-p) tolyl violuric acids [N-H2(o-m-p)TVA] with La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Dy(III), and Ho(III) have been determined potentiometrically in 50 Vol% ethanol water media at 25°C and at an ionic strength of 0.1 M NaClO4. The stability of the complexes follow the order of basicities of ligands and also the electron affinities of rare earths as measured by their overall ionisation potential. The order of stabilities of rare earths with violuric acids is, La3+ < Ce3+ < Pr3+ < Nd3+ < Sm3+ < Gd3+ < Eu3+ < Dy3+ < Ho3+. 相似文献
11.
Rare examples of amido‐iodo complexes of selected divalent lanthanides can be synthesized by using deprotonated Ap*H {Ap*H = 2,6‐diisopropylphenyl)‐[6‐(2,4,6‐triisopropylphenyl)‐pyridin‐2‐yl]‐amine} as a stabilizing ligand. Reaction of [Ap*K]n with [LnI2(thf)n] (Ln = Eu, Yb, n = 4,5) in THF leads to [Ln(Ap*)I(thf)2]2 (Ln = Eu, Yb). An attempted reduction of these divalent heteroleptic complexes with KC8 to synthesize complexes containing an unsupported Ln–Ln bond resulted in the formation of [Ln(Ap*)2(thf)2]. These lanthanide complexes were characterized by X‐ray structure analysis. 相似文献
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Hydrazinium oxydiacetate salts of formulae N2H5(Hoda)⋅H2oda, N2H5(Hoda) and (N2H5)2oda (H2oda=oxydiacetic acid) and complexes of the types, M(oda)⋅2N2H4⋅xH2O (where M=Co, Ni and Cd; x=0 for Co and Ni;x=1 for Cd) and Zn(oda)⋅N2H4⋅H2O have been prepared and characterized by analytical, spectral, thermal and X-ray powder diffraction data. IR data document
the existence of N2H+
5 ion in the simple salts and the bidentate coordination of both hydrazine and dianion in the complexes. Complete decomposition
of hydrazinium salts takes place via oxydiacetic acid intermediate. Cobalt and nickel complexes decompose in a single step,
whereas zinc and cadmium complexes decompose through hydrazinate intermediates. However, all the metal complexes yield metal
oxide as the final residue. Isomorphic nature of the cobalt and nickel complexes is evident from XRD data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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小檗碱与稀土硝酸盐二元配合物的合成、表征及抑菌作用 总被引:1,自引:0,他引:1
合成具有抑菌活性的稀土配合物,筛选具有抑菌活性的中药成分做有机配体合成稀土配合物.在乙醇溶液中合成了八种小檗碱与稀土硝酸盐的二元配合物,采用元素分析、红外光谱、差热-热重和X射线衍射等方法进行表征,确定配合物的化学组成为RE(NO3)3(B)3(RE=La3+,Sm3+,Nd3+,Dy3+,Pr3+,Y3+,Ce3+,Gd3+;B=C20H18NO4).研究了稀土配合物的抑菌活性,结果表明稀土配合物的抑菌效果较单独的稀土硝酸盐和小檗碱好. 相似文献
16.
Dr. Bo Liu Dr. Thierry Roisnel Prof. Dr. Jean‐François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13445-13462
[{N^N}M(X)(thf)n] alkyl (X=CH(SiMe3)2) and amide (X=N(SiMe3)2) complexes of alkaline earths (M=Ca, Sr, Ba) and divalent rare earths (YbII and EuII) bearing an iminoanilide ligand ({N^N}?) are presented. Remarkably, these complexes proved to be kinetically stable in solution. X‐ray diffraction studies allowed us to establish size–structure trends. Except for one case of oxidation with [{N^N}YbII{N(SiMe3)2}(thf)], all these complexes are stable under the catalytic conditions and constitute effective precatalysts for the cyclohydroamination of terminal aminoalkenes and the intermolecular hydroamination and intermolecular hydrophosphination of activated alkenes. Metals with equal sizes across alkaline earth and rare earth families display almost identical apparent catalytic activity and selectivity. Hydrocarbyl complexes are much better catalyst precursors than their amido analogues. In the case of cyclohydroamination, the apparent activity decreases with metal size: Ca>Sr>Ba, and the kinetic rate law agrees with RCHA=k[precatalyst]1[aminoalkene]1. The intermolecular hydroamination and hydrophosphination of styrene are anti‐Markovnikov regiospecific. In both cases, the apparent activity increases with the ionic radius (Ca<Sr<Ba) but the rate laws are different, and obey RHA=k[styrene]1[amine]1[precatalyst]1 and RHP=k[styrene]1[HPPh2]0[precatalyst]1, respectively. Mechanisms compatible with the rate laws and kinetic isotopic effects are proposed. [{N^N}Ba{N(SiMe3)2}(thf)2] ( 3 ) and [{N^N}Ba{CH(SiMe3)2}(thf)2] ( 10 ) are the first efficient Ba‐based precatalysts for intermolecular hydroamination and hydrophosphination, and display activity values that are above those reported so far. The potential of the precatalysts for C? N and C? P bond formation is detailed and a rare cyclohydroamination–intermolecular hydroamination “domino” sequence is presented. 相似文献
17.
稀土与L-谷氨酰胺配合物的电子能谱研究 总被引:5,自引:0,他引:5
合成了通式为LnL_3Cl_3·2H_2O(Ln=Eu,Tb,Ho,Tm;L=L-谷氨酰胺)的固体配合物。用XPS辅以元素分析、热分析及IR光谱研究了配合物的组成及性质。观察到配合物中O_(1a)、Ln_(3d)、Ln_(4d)和Cl_(2p)结合能的变化,并发现Eu配合物Eu_(3d)谱峰的伴峰结构,讨论了伴峰产生的机理。 相似文献
18.
合成了4种含半菁的新型稀土配合物:四(1-苯基-3-甲基-4-苯甲酰基吡唑啉酮-5)合稀土(La,Nd,Dy,Yb)酸(E)-1-十六烷基-4-(2,4'-二甲氨基苯基)乙烯基吡啶,用元素分析,紫外可见光谱,红外光谱,核磁共振谱,差热热重谱,X射线光电子能谱,X射线粉末衍射和摩尔电导对配合物进行表征。研究了4个配合物的空气-水(18℃,pH=5.6)界面上的表面压-面积(π-A)等温线行为和镝配合 相似文献
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铝,镁轻合金中的稀土 总被引:11,自引:3,他引:11
综述了稀土-镁和稀土-铝合金的晶体化学、热力学和相图数据,根据其前景特别注意了富镁,富铝稀土合金及添加稀土对合金性能的影响,报道了若干稀土-鲜、稀土-铝及含两个没稀土的镁、铝合金的研究结果。对富镁、富铝的二元和三元合金相的结晶及形成规律进行了总结和讨论,并对有确定结构的合金精细设计和可能的应用提出了建议。 相似文献
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Stability constants for La3+, Ce3+, UO2
2+, and Th4+ metal ion complexes with rhodanine azosulfonamide derivatives have been determined potentiometrically in 0.1 M KCl in a 30% (v/v) ethanol–water mixture. The order of the stability constants of the complexes found was to La3+ < Ce
2+ < UO
2
2+ < Th
4+. The influence of substituents on the stability of the complexes was examined on the basis of electron-repelling property of the substituent. The effect of temperature on the stability constants was studied and the Gibbs energy, the enthalpy, and entropy of complexation thermodynamic parameters were derived and are discussed. The stoichiometries of these complexes were determined conductometrically and the results indicated the formation of 1:1 and 1:2 (metal:ligand) complexes. 相似文献