Kinetic Studies on Forming Iso-nuclear β-type Chelates of Rare Earths with p-Sulphoaminobromophosphonazo

Some 2,7-bis(arylazo) derivatives of chromotropic acid can form chelates with rare earth ions in the 700-800 nm region, especially they can form iso-nuclear ?-type chelates which have higher molar absorbtivities and have been used for the determination of trace amounts of light lanthanides in the presence of heavy lanthanides1,2. Some papers3,4 have reported the kinetic behavior of forming homo-nuclear ?-type chelates. However, the information about forming iso-nuclear ?-type chelates is still…     

希土硼氢化物的研究--Ⅴ.十二氢十二硼酸N-氧化邻二氮杂菲合希土(Ⅲ)螯合物的合成

将希土氧化物或氢氧化物同N-氧化邻二氮杂菲及十二氢十二硼酸在水—乙醇介质中反应,合成了十三个十二氢十二硼酸N-氧化邻二氮杂菲合希土螯合物。通过元素分析、红外光谱、摩尔电导率的测量。确定螯合物的化学式为[Ln(phenO)_4]_2(B_(12)H_(12))_3·nH_2O。用DTA—TG法探讨了化合物的热行为。     

测定可逆反应动力学参数的一种新方法

提出了测定一级可逆反应速率常数的新方法,用以测定稀土的偶氮胂Ⅲ络合物与CyDTA交换反应的速率常数,并详细讨论了测定速率常数时动力学数据的选取原则。     

速差动力学因子分析法测定重稀土混合物

因子分析是解决多变量问题的一种数学方法,在化学中已应用于成分分析,但在速差动力学分析中常的应用未见报道。速差动力学分析中常用的曲线拟合法需先知道混合物的组成,并用纯组分求出动力学参数,而因子分析可不必事先知道组分数及求动力学参数。本文应用因子分析法测定重稀土的二元及三元混合物,得到较好的结果。     

Study and analytical application of rare earth inhibition of laccase

The effect of metal ions on the laccase-catalyzed redox reaction of 5,6-dibromo-2,3-dicyanohydroquinone to 5,6-dibromo-2,3-dicyanosemiquinone was studied. The results show that rare earth ions strongly inhibited the reaction, while most of the common elements such as Ca(2+), Mg(2+), Cu(2+), Zn(2+), Al(3+) and Fe(3+), etc. had no inhibition on the reaction. Further experimental results reveal that the inhibition of lanthanum (III) on laccase activity was of the comparative type and the degree of inhibition of La(3+) on laccase activity was proportional to the concentration of La(3+). Based on this, a simple, rapid and new stopped-flow enzyme-catalyzed analytical kinetic method for determination of rare earth was proposed and applied to the determination of trace amounts of rare earth in water.     

高锰酸钾-鲁米诺反应体系中碱土金属离子Mg2+,Ca2+,Sr2+,Ba2+化学发光行为研究

将被认为没有化学发光活性的第二主族(碱土金属)离子Mg^2 ,Ca^2 ,Sr^2 ,Ba^2 溶液注入到已充分反应的高锰酸钾与鲁米诺混合液中时,又发生了新的化学发光反应,并检测到强的化学发光信号．在对有关反应的动力学性质、化学发光光谱、紫外可见光谱及其它一系列实验研究的基础上,提出了可能的化学发光反应机理．同时,优化了反应条件,评价了这一反应用于Mg^2 ,Ca^2 ,Sr^2 ,Ba^2 分析的可行性．     

Synthesis and Characterization of Lanthanon Chelates of Thiohydroxamic Acids: Studies on Lanthanon Chelates of N-Thioacetyl-N-phenylhydroxylamine

Abstract

New chelates of lanthanon with N-thioacetyl-N-phenylhydroxylamine have been prepared. The available data and physical properties of the chelates indicate the attachment of each rare earth ion to three molecules of ligand and four molecules of water. This is supported by elemental analysis and UV and IR absorption spectra.     

Monopropionate analogues of DOTA4- and DTPA5-: kinetics of formation and dissociation of their lanthanide(III) complexes

The replacement of an acetate function of the macrocyclic DOTA4-(DO3A-Nprop4-) or the acyclic DTPA5- in terminal position (DTTA-Nprop5-) has been recently shown to result in a significant increase of the water exchange rate on the Gd3+ complexes, which makes these chelates potential contrast agents for MRI applications. Here, two novel and straightforward synthetic routes to H4DO3A-Nprop are described. Protonation constants of DO3A-Nprop4- and stability constants with several alkaline earth and transition metal ions have been determined by potentiometry. For each metal, the thermodynamic stability constant is decreased in comparison to the DOTA chelates. The formation reaction of LnDO3A-Nprop- complexes (Ln=Ce, Gd and Yb) proceeds via the rapid formation of a diprotonated intermediate and its subsequent deprotonation and rearrangement in a slow, OH- catalyzed process. The stability of the LnH2DO3A-Nprop* intermediates is similar to those reported for the corresponding DOTA analogues. The rate constants of the OH- catalyzed deprotonation step increase with decreasing lanthanide ion size, and are slightly higher than for DOTA complexes. The kinetic inertness of GdDTTA-Nprop2- was characterized by the rates of its exchange reactions with Zn2+ and Eu3+. The rate of the reaction between GdDTTA-Nprop2- and Zn2+ increases with Zn2+ concentration, while it is independent of pH, implying that the exchange takes place predominantly via direct attack of the metal ion on the complex. In the Eu3+ exchange, the rate decreases with increasing concentration of the exchanging ion which is accounted for by the transitional formation of a dinuclear GdDTTA-NpropEu+ species. The kinetic inertness of the monopropionate GdDTTA-Nprop2- is decreased in comparison to GdDTPA2-: all rate constants, characterizing the dissociation reaction via either proton- or metal-catalyzed pathways being higher by 1-2 orders of magnitude. Similarly, a study of the acid-catalyzed dissociation of the macrocyclic CeDO3A-Nprop- showed a partial loss of the kinetic inertness with regard to the tetraacetate derivative CeDOTA-.     

稀土配合物的荧光衰减动力学特性和时间分辨光谱分析研究

研究了稀土配合物的荧光衰减动力学特性及其影响因素,拟定出长寿命组份存在下测定短寿命组份及短寿命组份存在下测定长寿命组份的2种时间分辨荧光光谱分析方法。用于纯稀土氧化物及合成水样中痕量铕和镝的测定,获得了满意的结果。     

COMPLEXES OF GALLIUM(III) WITH HYDROXYAROMATIC LIGANDS

Abstract

The equilibria between gallium(III) ion and selected hydroxyaromatic and dihydroxyaromatic ligands at 25°C, μ=0.100 M (KNO₃) have been determined. Potentiometric measurements on 1:1, 2:1, and 3:1 molar ratios of ligand to Ga(III) have been made as a function of degree of neutralization over the entire accessible ?log [H⁺] scale. Calculations were carried out so as to take account of competing hydrolytic reactions, and formation constants of gallium(III) with chromotropic acid, 8-hydroxyquinoline-5-sulfonic acid, 5-sulfosalicylic acid, and 1,2-dihydroxy-benzene-3,5-disulfonic acid were obtained. Stable hydroxo chelates do not form under the reaction conditions employed. The protonation constants of the ligands and the formation constants of the gallium chelates are discussed and compared with previously published work on these gallium chelates and on chelates of “analogous” metal ions such as those of Fe(III) and A1(III).     

Luminescence studies on europium-strontium phthalate system

New lanthanide luminescence materials were prepared. The main component lanthanide chelates generally need a relatively high content of rare earth. Inorganic luminescence materials only need low rare earth concentration using doped method. Similarly, lanthanide chelates can be added to complex matrix by doped method. In this way, low rare earth concentration emission was successful in the lanthanide chelates system as well. The influence of europium ion concentration on luminescence intensities was discussed. When the europium ion weight in the complex is only about 0.6%, the sample exhibits good luminescence properties. The fluorescence, Fourier transform infrared spectra, micro-Raman and electron spin resonance spectra of the samples were measured. And a possible luminescence mechanism was suggested by the inorganic doped mechanism and the luminescence of lanthanide complexes together.     

近红外发光稀土配合物及杂化材料研究进展

稀土因其特殊的物理和化学性质,在信息技术、能源技术、生物技术等高科技领域及国防建设等方面都起着非常重要的作用,中国作为稀土大国,十分重视对稀土材料的研究和开发。稀土离子近红外发光(750～1700 nm)在激光和光纤通讯、医学诊断、免疫分析等热门领域的潜在应用,受到了科研人员的极大关注。稀土离子本身发光极弱,通过分子内传能有机配体可以敏化稀土离子发光,但稀土配合物常受外界干扰,其稳定性较差,若将其与凝胶、介孔材料、离子液体等无机基质复合,得到具有良好光、热稳定性和化学稳定性的有机/无机杂化材料。总结了近些年来近红外发光稀土配合物及近红外发光稀土杂化材料的研究进展,并对其发展前景进行了展望。     

Structure and behavior of organic analytical reagents : Chelates of 2-(o-hydroxyphenyl)-benzoxazole, 2-(o-hydroxyphenyl)-benzothiazole and 2-(o-hydroxyphenyl)-benzothiazoline.

The reactions of the chelating reagents named in the title, with a number of metal ions, have been studied in order to evaluate the behavior of reagents containing reactive groupings analogous to those of 8-hydroxyquinoline, but so arranged as to form six-membered ring chelates with metal ions. All three reagents have been found to give less stable chelates than 8-hydroxyquinoline, indicating that for this type of reagent, six-membered ring chelates are less stable than five. 2-(o-Hydroxy-phenyl)-benzoxazole and 2-(o-hydroxyphenyl)-benzothiazole have been found to be potentially useful as organic precipitating agents for metal ions, being more selective than 8-hydroxyquinoline, which they somewhat resemble in behavior. In contrast to the oxazole and thiazole, 2-(o-hydroxyphenyl)-benzothiazoline was found to react with most of the metal ions tried. Because of the solubility of its chelates in organic solvents, 2-(o-hydroxyphenyl)-benzothiazoline may be a useful solvent extraction agent for metal ions.     

稀土(III)-冠醚配位反应的热力学性质I:稀土(III)高氯酸盐与苯-15-冠-5-在乙腈溶液中配位反应的量热滴定研究

用量热滴定法于298.15K测定了除钪、钷以外的全部十五种稀土(III)高氯酸盐与苯并-15-冠-5在乙腈溶液中的配位作用。借助计算机算出了配合物的稳定常数和配位焓, 进而算出了配位自由能和配位熵。结果表明:十五种稀土(III)离子与苯并-15-冠-5都可以配位, 配位焓为正值;La^3^+配合物最稳定, Ce^3^+次之, 其余稀土(III)离子配合物稳定性变小, 但彼此差别不大, 在Tb处有突变;熵在配合物形成时起稳定化作用。     

混合稀土氯化物催化的Diels-Alder反应

本文提出以混合烯土氯化物作为Diels-Alder反应催化剂, 催化三种有工业应用价值的环加成反应。实验结果表明, 混合稀土氯化物对具有含氧基团底物的Diels-Alder反应催化效果显著, 其中混合重烯土氯化物比混合轻稀土氯化物表现出更高的催化活性。。     

稀土配合物的时间分辨光谱分析法研究(Ⅰ)TFA-TOPO-农乳-100体系用于测定铕和钐

本文采用自己组装的时间分辨荧光光谱测定装置,研究了铕(钐)-三氟乙酰丙酮-三正辛基膦化氧(Eu(Sm)-TFA-TOPO)在非离子表面活性剂农乳-100存在下的光谱特性、荧光衰减动力学特性和发光机理。提出了能量传递机制和第二配体TOPO在荧光发射过程中的作用,制定出TFA-TOPO-农乳-100体系测定痕量铕和钐的时间分辨荧光光谱分析方法,用于测定高纯氧化钇中的痕量铕和钐,结果令人满意。     

偶氮氯膦Ⅲ吸光光度法测定轻、重稀土元素和钇

本文研究了稀土元素与偶氮氯膦Ⅲ的α型及β型显色反应。在一定条件下,重稀土元素(Gd-Lu)同偶氮氯膦Ⅲ螯合物可由α型转变成β型,其中钇的螯合物转成β型倾向最大,而轻稀土元素在相同条件下仅形成α型,利用Zn-EDTA和Zn-CyDTA的掩蔽效应,可扩大显色反应的差异性。提出了在HCl-NaAc介质中分别测定轻、重稀土元素及钇的方法:在pH2.9-3.4范围内,用Zn-CyDTA作掩蔽剂,可在重稀土存在下测定轻稀土元素。在pH1.8-2.4和pH2.8-3.6,用Zn-EDTA、NaF或NaF作掩蔽剂可分别测定钇及重稀土元素。     

Collision-induced dissociation of the lower alcohols. A thermochemical study

Collision-induced dissociation of the molecular ions and of some of the fragment ions foremed on ionization of methanol, ethanol and n-propnol have been studied at high energy resolution in a mass spectrometer. The translational energy lost upon collision and the kinetic energy releasedupon fragmentation of the collisionally excited species have been measured by the methods of ion kinetic energy spectromety. The results of the translational energy loss measurements compare well with excitation energies predicted for each reaction form breakdown curves showing the relative abundances of the ionsas a fuction of internal energy. This correspondence is evidebce that the ionic reactions following electron-impact excitation and those following collisional excitation with neutral molecules at relative traslational energies in the range of several kilovolts are at least qualitatively independent of the method of excitation. The occurrence of the corresponding spontaneous fragmentations in the alcohols has also been studied and the kinetic energy releases accompanying these reactions have been determined. In a few cases, metastable peaks were observed which did not increase in intensity when collision gas added and this phenomenon is associated with particular features of the reaction thermochemistry. Reactions which generally occur to very small extents in mass spectromety, such as methylene elimination, have been observed in highly excited ions. The methods developed in this study allow the decription of the thermochemistry of the reaction of highly excited ions, indlcuding the experimental determination of the partitioning of the nonfixed energy of the activated complex. This procedure complemets and extends energy partitioning studies made on metastable ions in which the partitioning of the reverse activation energy is the more readily accessible.     

Kinetik sehr schneller Methylquecksilber-Übertragungsreaktionen zwischen pyridinhaltigen Chelatliganden und dem Hydroxid-Ion

Kinetics of very fast Methylmercury-Transfer Reactions between Pyridine-containing Chelating Ligands and the Hydroxide Ion The kinetics of the reactions between methylmercury hydroxide and bipyridine, terpyridine, phenanthroline and pyridine-2-azo-4-dimethylaniline have been studied by means of the temperature jump relaxation method. These bi- and tridentate ligands form methylmercury chelates. Their formation is faster than the formation of the pyridine complex. The chelate complexes show an unusually high reactivity. Their reaction rates with hydroxide ions reach almost the diffusion controlled limit.     

环烷酸类载体液膜体系对金属离子传输机理的研究

本文先在大块液膜体系中以环已烷甲酸为载体,通过正交设计,系统地研究了各种因素对希土离子输送作用的影响规律。比较了相同条件下RE~(3+)(希土)同Na~+,NH_4~+、Ca~(2+)和Fe~(3+)等离子的输送作用。发现在适当条件下,无皂化的羧酸载体对RE~(3+)离子具有良好的输送效果,同时证实,羧酸输送RE~(3+)离子是通过三个H~+离子与一个RE~(3+)离子的交换,而当载体皂化时,皂化的载体直接与接收相H~+离子发生交换,从而降低了羧酸对RE~(3+)离子的输送和分离效果。 在大块液膜研究的基础上,建立了一个以无皂化的环烷酸为载体的乳状液膜体系,从模拟离子矿的硫酸铵浸出液中萃取希土,通过正交试验确定了最优的液膜萃取条件,希土萃取率达96％以上,富集度30～40倍。