Hydration and Ion Pairing in Aqueous Sodium Oxalate Solutions

Dielectric spectra have been measured for aqueous sodium oxalate solutions up to the saturation concentration (0.04≤c [mmol L^?1]≤0.25) at 25 °C over the approximate frequency range 0.2≤ν [GHz]≤20. The spectra exhibit a process at about 1 GHz associated with the presence of ion pairs, in addition to the dominant solvent relaxation process at about 18 GHz. Detailed analysis of the solvent dispersion amplitude indicates that the oxalate ion is highly hydrated but that its solvation sheath is “fragile”, decreasing quickly with increasing solute concentration. The NaOx(aq)^? ion pair is shown to be of the double‐solvent‐separated (2SIP) type, with an infinite dilution association constant K_A=1.04±0.02. Analysis of the ion‐pair relaxation time as a function of solute concentration gave rate constants for the formation (k₁₂=(7.3±0.4)10⁹ L mol^?1 s^?1) and dissociation (k₂₁=(6.7±0.5)10⁸ s^?1) of the ion pair. These values are reasonably close to the diffusion‐controlled values predicted by the Eigen theory, consistent with a 2SIP structure for the ion pair.     

水杨醛亚胺镍配合物催化的乙烯水相聚合

在含表面活性剂的水相体系中, 用一系列水杨醛亚胺镍配合物催化乙烯聚合, 得到了高分子量低支化度聚乙烯. 研究表明水杨醛亚胺镍配合物中苯环上取代基的电子效应和空间位阻对乙烯聚合活性和聚合物的分子量有所影响. 提高配合物酚氧环上取代基的吸电子性, 聚合活性相应增加, 但聚乙烯的分子量降低; 而增加苯胺环上取代基的空间位阻, 聚合活性和聚乙烯的分子量均增加. 粘度法测得由水相聚合得到的聚乙烯的分子量在10⁴～10⁵范围内. DSC测得该聚乙烯的结晶度在50%～70%之间, 熔点在115～137 ℃范围内. GPC分析表明用环辛二烯合镍[Ni(COD)₂]助催化乙烯, 聚乙烯的分子量分布随酚氧环上取代基电负性增加而从双峰到单峰变化, 动态流变学研究进一步说明了聚乙烯分子量及其分布的变化.     

Cobalt(II) Oxide Solubility and Phase Stability in Alkaline Media at Elevated Temperatures

A platinum-lined, flowing autoclave facility was used to investigate the solubility behavior of cobalt(II) oxide (CoO) in deoxygenated ammonium and sodium hydroxide solutions between 22 and 288°C. Co(II) ion activity in aqueous solution was controlled by a hydrous Co(II) oxide when nitrogen was used for deoxygenation and by metallic cobalt when hydrogen was used. Measured cobalt solubilities are interpreted using a Co(II) ion hydroxo- and amminocomplexing model and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. A common set of thermodynamic properties for the species Co(OH)⁺, Co(OH)₂(aq) and Co(OH)(NH₃)⁺ is provided to permit accurate cobalt oxide solubility calculations over broad ranges of temperature and alkalinity.     

Nickel(II) Oxide Solubility and Phase Stability in High Temperature Aqueous Solutions

A platinum-lined, flowing autoclave facility was used to investigate the solubility behavior of nickel(II) oxide (NiO) in deoxygenated ammonium and sodium hydroxide solutions, between 21 and 315°C. Solubilities were found to vary between 0.4 and 400 nmol-kg^–1. The measured nickel ion solubilities were interpreted via a Ni(II) ion hydroxo- and ammino-complexing model, and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. Two solid phase transformations were observed: at temperatures below 149°C, the activity of Ni(II) ions in aqueous solution was controlled by a hydrous Ni(II) oxide (theophrastite) solid phase rather than by anhydrous NiO (bunsenite); above 247°C, Ni(II) activities were controlled by cubic rather than by rhombohedral bunsenite.     

四氮大环-金属配合物与DNA作用的电化学及谱学研究

Mononuclear copper（Ⅱ）, nickel（Ⅱ） and cobalt（Ⅲ） tetracoordinate macrocyclic complexes were synthesized and spectroscopically characterized. The crystal structure of the three compounds were determined by X-ray crystallography. The electrochemical experimental results indicate that the three complexes could interact with DNA mainly by electrostatic interaction. The interaction of tetracoordinate macrocyclic cobalt（Ⅲ） complex with DNA was studied by cyclic voltammetry and UV-vis spectroscopy. The experimental results reveal that tetracoordinate macrocyc- lic cobalt（Ⅲ） complex could interact with DNA by electrostatic interaction to form a 1 ： 1 DNA association complex with a binding constant of 7.50 ×10^3 L·mol^-1.     

氯化银比浊法测定镍钴锰三元素氢氧化物中氯离子含量

研究了氯化银比浊法测定镍钴锰三元素氢氧化物中氯离子含量的测定方法。选择了合适的测定波长,并对硝酸用量、沉淀剂用量、稳定时间的影响进行了试验,确定了较优的分析条件。样品加标回收率在95%-103.3%,氯离子浓度在0-4μg/mL与浊度值有良好线性关系。方法为控制镍钴锰三元素氢氧化物中氯离子提供了检测依据。     

Simultaneous Determination of Nickel(II) and Cobalt(II) by Second-Derivative Spectrophotometry

4-(2-Pyridylazo) resorcinol, PAR, is shown to be useful for simultaneous determination of cobalt(II) and nickel(II) using second-derivative spectrophotometric method with controlled experimental parameters. This method allows the determination of 0.20-1.25 ppm of nickel(II) and 0.25-1.50 ppm of cobalt(II) in mixtures with good precision and accuracy. This method has advantages of simplicity, speed and requires no prior separations.     

Structural Studies on Saturated Aqueous Solutions of Manganese(II), Cobalt(II), and Nickel(II) Chlorides by X-ray Diffraction

As a part of our studies on crystallization processes of electrolytes, the structure of aqueous solutions of MCl₂ (M = Mn, Co, Ni) equilibrated with hydrate crystals, MCl₂ · mH₂O (m = 6, 4, 2), was investigated by means of X-ray diffraction at 25, 40, 55, and 70°C. The complexes formed in MnCl₂ solutions, were found to be mixed–ligand chloroaqua octahedral complexes of M²⁺ ions with the Mn—O and Mn—Cl distances of about 220 and 251 pm, respectively. The average number of Mn—Cl and Mn—O interactions increased from 1.2 to 1.9 and decreased from 4.8 to 4.1, respectively, with changing MnCl₂ solutions from Mn25 (MnCl₂ solution at 25°C) to Mn70 (MnCl₂ solution at 70°C). In the octahedral species of Co²⁺, the Co—O and Co—Cl distances were found to be about 211 and 240 pm, respectively. With an increase in the saturated concentration by changing temperature from 25 to 70°C, the average coordination number of the Co—Cl contact per Co²⁺ increased from 0.5 to 1.2, and the average number of Co—O interactions decreased from 5.5 to 4.8. The structural analysis was carried out by taking into consideration the existence of the tetrahedral species in the solutions saturated at 40, 55, and 70°C, on the assumption of the existence of [CoCl₄]^2–. The Co—Cl distance was found to be 228 pm, while the number of Co—Cl interactions in the [CoCl₄] complex was calculated to be 3.7 by the least-squares calculations. The Ni—O and Ni—Cl distances were estimated to be about 206 and 237 pm, respectively. The frequency factor n of the Ni—O and Ni—Cl interactions decreased monotonously from 5.6 to 5.0 and increased from 0.4 to 1.0, respectively, with increasing NiCl₂ concentration. The n values of the Co—Cl and Ni—Cl interactions of the octahedral complexes increased sharply with concentration at higher concentrations. Comparing structures of the complexes in the saturated solutions and the hydrate crystals of these metal ions, we discussed a role of the complexing species on crystallization of the hydrates.     

氯化银比浊法测定镍钴锰三元素氢氧化物中氯离子

建立了氯化银比浊法测定镍钴锰三元素氢氧化物中氯离子含量的测定方法。选择了合适的测定波长,并对硝酸用量、沉淀剂用量、稳定时间对测定结果的影响进行了试验,确定了较优的分析条件。样品加标回收率在95%~103.3%,氯离子浓度在0~4μg/mL与浊度值有良好线性关系。方法为控制镍钴锰三元素氢氧化物中氯离子提供了检测依据。     

Thermogravimetric Analysis of Cobalt(II)-dothiepin Complexes

The complexes of cobalt(II) with dothiepin (DOT) hydrochloride have been studied for kinetics of thermal degradation by thermogravimetric analysis (TG) and derivative thermogravimetric studies (DTG) in a static nitrogen atmosphere at a heating rate of 10° C min⁻¹. A general mechanism of thermal decomposition is advanced involving dehydration and decomposition process for both organic and inorganic ligands. The thermal degradation reactions were found to proceed in three steps having an activation energy in the range 6.75–170 kJ mol⁻¹. Thermal decomposition kinetics parameters were computed on the basis of thermal decomposition data. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal Decompositions of the Molybdotellurates of Nickel(II) and Cobalt(II)

Molybdotellurates [M(H₂O)₆]₃·[TeMo₆O₂₄], with M=Ni(II) and Co(II), were synthesized and characterized by single-crystal X-ray diffraction for compound 1 and X-ray powder diffraction for compound 2, EDAX, IR, electronic spectra in the solid phase and in solution, and magnetic properties. Thermogravimetry and differential scanning calorimetry of both compounds revealed a loss of 11 water molecules through an endothermal process with ΔH=800 kJ mol⁻¹ for the nickel compound and ΔH=833 kJ mol⁻¹ for the cobalt compound. The residual compounds were characterized by chemical analysis, IR and XPS spectroscopy This revised version was published online in July 2006 with corrections to the Cover Date.     

四碘代对苯二甲酸根桥联的双钴(II)配合物的研究

报导了四种新的双核钴（Ⅱ）配合物，即［Co2（4I-TPHA）（L）4］（COl4）（4I-TPHA＝四碘代对苯二甲酸根阴离子，L＝1，10菲咯啉（phen）（1），5-硝基-,10菲咯啉（NO2-phen）（2），2，2′-联吡啶（bpy）（3）和4，4′-二甲基-2，2′-联吡啶（Me2bpy）（4）的合成和表征，配合物的磁性研究表明双核钴（Ⅱ）离子间有弱的反铁磁性自旋交换相互作用。     

高温及超临界条件下 MgCl2与CaCl2水溶液中离子水化与缔合的量子化学计算

对NaCl等碱金属水溶液的研究表明,室温条件下,离子在溶液中以水合形式存在,而在高温及超临界时,阴阳离子将结合成为离子对．采用量子化学计算,研究了MgCl2与CaCl2水溶液中水化与缔合的情况．通过Gaussian98软件包计算了阳离子的水化自由能以及离子对的生成能,从而获得水合离子与离子对的热力学稳定性及其随温度、压力的变化情况．通过比较热力学稳定性,考察了两种溶液中水化与缔合的变化情况．研究结果表明,MgCl2与CaCl2水溶液中离子水化与缔合的变化趋势与碱金属溶液基本一致,但是存在一个过渡区域,该区域内离子对与水合离子共存,因此需要采用不同于碱金属溶液的方法处理MgCl2与CaCl2水溶液．     

Nickel(II) and copper(II) complexes of aza macrocycles derived from trichloromethane

Syntheses of nickel(II) complexes of the tetraaza macrocycles 2,7-dichloro-1,3,6,8-tetraazacyclodecane (DCCD) and 2,8-dichloro-1,3,7,9-tetraazacyclododecane (DICD) and a copper(II) complex of 2,6,8,12,13,17-hexaazabicyclo[5.5.5]heptadecane (HBCH) are reported in the template condensation of trichloromethane with 1,2-diaminoethane or 1,3-diaminopropane. Formulation of the synthesized products [Ni(DCCD)(H₂O)₂]Cl₂, [Ni(DICD)(H₂O)₂]Cl₂?·?H₂O, and [Cu₃(HBCH)(H₂O)₆]Cl₆, and the metal-free ligand hydrochloride HBCH?·?6HCl has been confirmed by elemental analyses, conductivity measurements, and spectral studies. Potentiometric studies of nickel(II) and copper(II) complexes of HBCH and structurally similar 2,5,8,10,13,16,17,20,23-nonaazabicyclo[7.7.7]tricosane (NACT, earlier derived from trichloromethane and diethylenetriamine) have also been performed in the structural support of HBCH. In 1?:?1, metal?:?HBCH solution, copper(II) is coordinated to four N-donors of two-HN(CH₂)₃NH– groups of the ligand in a non-planar tetraaza cavity. The equilibrium constant value (log?K?=?15.41) for the reaction Cu^2+?+?A???CuA²⁺ (A?=?HBCH) is in favor of the cyclic structure of the ligand. A high value (log?K?=?23.27) for corresponding reaction in the NACT system is due to conformational change in the ligand, where copper(II) organizes the macrocycle to form a nearly planar cavity in which the cation fits well.     

Darstellung und Strukturanalyse neuer Komplexe von Eisen(II), Cobalt(II) und Nickel(II) nach synergistischer Extraktion

Zusammenfassung Die synergistische Extraktion von Eisen(II)-, Cobalt(II)- und Nickel(II)-Komplexen wird untersucht. Verwendet werden fluorierte Diketone (A) (Derivate des Thenoyltrifluoracetons) und eine neue Gruppe Schiff' scher Basen. Aus den Extraktionskurven nach der Job- und Molar-Ratio-Methode, der Elementaranalyse und aus Molmassenbestimmungen werden Komplexverbindungen der Zusammensetzung [M₄A₈B⁴] nachgewiesen. Aus den Elektronen- und IR-Spektren und aus magnetischen Messungen wird für die Ni(II)-Komplexe eine octaedrische Struktur vorgeschlagen.

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Preparation and structure analysis of new iron(II), cobalt(II) and nickel(II) complexes by synergistic extraction

Summary The synergistic extraction of iron(II), cobalt(II) and nickel(II) complexes was investigated. Fluorinated diketones (A) (derivates of thenoyltrifluoracetones) and a new group of Schiff bases were used. By Job and molar-ratio method investigation on the extraction curves, by elementary analysis and molar mass detection, complex compounds of the composition [M₄A₈B⁴] could be proved. Electron and infrared spectra and magnetical measurements led to an octahedral structure proposal for the Ni(II)-complexes.

Mein Dank gilt besonders Herrn Professor Dr. H. Specker, Direktor des Instituts für Anorganische Chemie I der RUB, für die Zurverfügungstellung der Geräte und Chemikalien, Herrn Professor Dr. Metfessel und Frau Dr. Magdela Gronau für die magnetischen Messungen in der Abteilung Physik der RUB.     

Thermal Analysis of Cobalt(II) Salts with some Carboxylic Acids

The thermal analysis of CoC₂O₄·2H₂O, Co(HCOO)₂·2H₂O and Co(CH₃COO)₂·4H₂O was carried out with simultaneous TG-DTG-DTA measurements under non-isothermal conditions in air and argon atmospheres. The intermediates and the end products of decomposition were characterised by X-ray diffraction and IR and UV-VIS spectroscopy. The decomposition of the studied compounds occur in several stages. The first stage of dissociation of each compound is dehydration both in air and argon. The next stages differ in air and argon. The final product of the decomposition of each compound in air is Co₃O₄. In argon it is a mixture of Co and CoO for cobalt(II) oxalate and cobalt(II) formate but CoO for cobalt(II) acetate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Untersuchungen und Strukturanalyse von Eisen(II)-, Cobalt(II)- und Nickel(II)-Komplexen nach synergistischer Extraktion

Zusammenfassung Die synergistische Extraktion von Eisen(II)-, Cobalt(II)- und Nickel(II)-Komplexen wird untersucht. Verwendet wurden fluorierte Diketone (A) (Hexafluoroacetylaceton und Derivate des Thenoyltrifluoracetons) und Abkömmlinge des Pyridinal(2)-phenylimins und des Bis-(pyridinal-2-)-diimines (B). Aus den Extraktionskurven nach der Job- und der Molar-Ratio-Methode, der Elementaranalyse und aus Molmassenbestimmungen werden Komplexverbindungen der Zusammensetzung [MA₂B¹], [M₂A₄B²] und [M₃A₆B³] nachgewiesen. Aus den Elektronen- und IR-Spektren und aus magnetischen Messungen wird für die Ni(II)-Komplexe eine octaedrische Struktur vorgeschlagen.

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Investigation and structure analysis of iron(II), cobalt(II) and nickel(II) complexes after synergistic extraction

Summary The synergistic extraction of iron(II), cobalt(II) and nickel(II) complexes was investigated. Fluorinated diketones (A) (hexafluoroacetylacetone and derivatives of thenoyltrifluoracetones) and derivatives of pyridinale(2)-phenylimine and bis(pyridinale-2-)diimine (B) were used. By Job and molar-ratio investigation on the extraction curves, by elementary analysis and molar mass detection complex compounds of the composition [MA₂B¹], [M₂A₄B²] and [M₃A₆B³] could be proved. Electron and infrared spectra and magnetical measurements led to an octahedral structure proposal for the Ni(II)-complexes.

Wir danken Herrn Dr. Bodo Plewinsky, Institut für Anorganische Chemie der FU Berlin, sehr herzlich für die Bestimmung der Molmassen mit der Ultrazentrifuge.     

基于T-T碱基错配的荧光传感器特异性检测汞离子

在本文中,我们研制了一种基于T-T碱基错配特异性键合汞离子的荧光传感器用于汞离子的检测。该传感器由两条分别标记了荧光基团（F）和淬灭基团（Q）的DNA探针组成,并且含有两对用于结合汞离子的T-T错配碱基。当汞离子存在时,两条探针之间形成T-Hg2+-T结构,作用力增强,从而拉近了荧光基团与淬灭基团之间的距离,发生能量转移,使荧光信号在一定程度上被淬灭。在优化的条件下,我们使用该传感器对汞离子进行检测,动力学响应范围为50nM到1000nM,线性相关方程为y= 5281.13 - 1650.56 lg[Hg2+] ( R2 = 0.985),检测下限为79nM。此外,我们还考察了该传感器的选择性,当用其它干扰离子（浓度都为1.0µM）代替待测离子进行实验时,没有发生明显的荧光淬灭,说明该传感器具有较高的选择性。该传感器的构建为汞离子的检测提供了一条快速、简便的新途径。     

Angular Overlap Studies of Mono-(Aminodiphosphonato)Copper(II) Complexes in Aqueous Solutions

Electronic absorption spectra of copper(II) complexes with iminodimethylenephosphonates R-N(CH₂PO₃H₂)₂ type (L, R-dmp), in aqueous solution have been characterized and quantitatively interpreted. The geometry of species in aqueous solution at pH 7–8 has been assumed on the basis of our previous combination of UV spectrophotometric measurements and ESR spectra, as well as data obtained from potentiometric titration. The ligand-field spectra (d–d transitions) of the [CuL(H₂O)_x]^2– chromophores (where x = 2, 3) have been treated by the angular overlap model (AOM) and C _2v symmetry. Low-symmetry splittings of the broad asymmetric bands in the spectra of solutions at room temperature were resolved by Gaussian analysis. The effect of the and bonding of the tridentate (and tetradentate) ligands (with oxygen-donor and nitrogen-donor ligators) on the central metal ion has been described in the ligand-field framework.     

Syntheses and Crystal Structures of Cobalt(II) and Nickel(II) Coordination Polymers with 3-Aminobenzoic Acid Ligand

1 INTRODUCTION Much research interest has been focused on metal- organic coordination polymers in past years because of the structural and topological novelty of these compounds and their potential applications as func- tional materials, such as catalyst, ion-exchange, gas sorption, optical material and molecule-based ma- gnet[1~6]. In this field, many organic bridging ligands such as bipyridine, polyaromatic carboxylate and re- lated species have been used to produce various types of met…