Interpretation of the Parameters of the EPR Spectra of Transition Metal Complexes

The calculated parameters of the EPR spectra of complexes of d¹ and d⁹ ions were presented. The covalent bond parameters used in the calculations were determined from EPR and experimental optical data (inverse problem of EPR spectroscopy). Various contributions to the expressions for the EPR parameters were compared. The observed abnormal values of the EPR parameters were discussed. The effects of charge-transfer states and the vibronic coupling on the components of g, A, and A^L tensors were considered. Mechanisms of spin density transfer to ligands in paramagnetic complexes were proposed.     

Calixarene Complexes with Transition Metal Ions

Selected calixarene complexes with transition metal ions are described showing their syntheses and possible applications, especially in the aspect of the environmental protection.This revised version was published online in July 2005 with a corrected issue number.     

EPR Study of Covalent Bond in Transition Metal Complexes

The results of a study of a covalent bond in the anitibonding and bonding states of d¹ and d⁹ complexes obtained by analyzing the EPR and optical data are presented. The nature of the electron density delocalization in some of the complexes is discussed. The effect of the charge-transfer states on the covalent bond structure is considered. The vibronic effect on the ground state function is discussed. The electronic distributions determined from EPR spectra by different approximation methods are compared.     

Thermal Studies on Solid Complexes of Saccharin with Divalent Transition Metal Ions

The thermal decompositions of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of saccharin were studied in static air atmosphere. All of the complexes contain four molecules of coordination water and two molecules of crystallization water. The water molecules were removed in a single stage, except from the Zn(II) complex, which exhibited two endothermic effects. The dehydration process was usually accompanied by a sharp colour change. The anhydrous complexes exhibited a phase transition and the decomposition or combustion of saccharin occurred in the second and subsequent stages. The final decomposition products were identified by XRPD as the respective metal oxides. The kinetic parameters, such as the order of reaction and energy of activation for the dehydration stage, were evaluated and the thermal stabilities of the complexes are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal Studies on Solid Complexes of Uracil With Some Divalent Transition Metal Ions

The thermal behaviour of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pd(II) complexes of uracil was studied by TG, DTG and DTA in a dynamic nitrogen atmosphere. Two processes occur in the isolated uracil complexes: dehydration and pyrolytic decomposition. In the hydrated complexes, the first stage observed was the loss of water molecules, which was followed by decomposition of the uracil. The thermal dehydration of the complexes occurred in from one to three steps. The final decomposition products were found to be the respective metal oxides, except in the cases of the Co(II) and Pd(II) complexes, which produced metallic cobalt and palladium, respectively. The order of reaction and energy of activation for the dehydration stage were evaluated.This revised version was published online in November 2005 with corrections to the Cover Date.     

Interpretation of the Electronic Spectra of Ruthenium Nitrosyl Complexes with Nitrogen-containing Heterocyclic Ligands

The electronic absorption spectra of ruthenium nitrosyl complexes with nitrogen-containing heterocyclic ligands were analyzed on the basis of ab initio and CINDO/CI semiempirical calculations of free ligands L and complexes trans-[Ru(NO)(NH₃)₄(L)]^{3 +} (L = pyridine, pyrazine, nicotinamide, isonicotinamide, l-histidine, imidazole). Spectral manifestations of a strong covalent Ru-NO bond were observed to conclude that the oxidation states of Ru and NO in the RuNO^{3 +} group are expedient to represent as Ru(III) and NO⁰. Introduction of a nitrosyl group into the inner coordination sphere of Ru(II) complexes with nitrogen-containing heterocyclic ligands much affects the entire spectral patterns and denudes these ligands of the capacity to exhibit chromophoric properties.     

Pyridino Nitrosyl Complexes of Rhenium

Preparation of pyridine derivatives of ReCl₃(NO) viz. (pyH)₂ReCl₅(NO), pyH[ReCl₄py(NO)], H[ReCl₄py(NO)], K[ReCl₄py(NO)], Ag[ReCl₄py(NO)] and [ReCl₃py₂(NO)] are described. All these compounds are stable solids. They are characterised by their analytical composition, spectral data, conductance and magnetic moment values.     

Room-Temperature Photogeneration of Nitrosyl Linkage Isomers in Ruthenium Nitrosyl Complexes

The conditions for the photogeneration of NO linkage isomers at room temperature are studied. By pulsed laser irradiation in the blue spectral range, the long-lived Ru−ON isomer can be generated at room temperature, which is crucial for potential applications, such as holography and data storage. By using static and time-resolved spectroscopy (UV/Vis and IR), we give evidence that the liftime of the Ru−(η²-(NO)) isomer is a decisive parameter for the formation of the Ru−ON isomer at high temperature owing to a two-step isomerization mechanism Ru−NO→Ru−(η²-(NO))→Ru−ON. Furthermore, we report the low-temperature structures for each isomer, which were revealed by photocrystallography.     

Electrochromatographic Separation of DMSO Complexes of Metal Ions

Abstract

Electrochromatography of DMSO complexes of fourteen metal ions have been performed in five electrolytes at 100 volts for 3 hrs. The mechanism of migration has been explained and a number of separations of metal-DMSO complexes were achieved.     

Syntheses of Transition Metal Complexes of Pentafluorophenylhydrazine

By reaction of pentafluorophenylhydrazine with metal chlorides the complexes M(NH₂NHC₆F₅)₄Cl₂ (M = Co, Ni), M(NH₂NHC₆F₅)₂Cl₂ (M = Mn, Fe, Pd, Zn, Cd), Cu(NH₂NHC₆F₅)Cl, and Hg(NH₂NHC₆F₅)₂Cl were obtained. From Cr(CO)₆ and pentafluorophenylhydrazine the complex Cr(CO)₅(NH₂NHC₆F₅) was synthesized.     

Transition Metal Complexes of an Antipyrine Derivative

The stepwise formation constants of N-antipyrinyl-N′-3-phenyl-2-propenoyl-thiourea (I) complexes with metal ions of the first transition series, Cu(II), Ni(II), Co(II), Mn(II) and Zn(II) have been determined in 70% (V/V) ethanol-water medium. The formation constants for the chelates follow the Irving-Williams series: Zn(II)<Cu(II)>Ni(II)>Co(II)>Mn(II) The effect of ionic radius and electronegativity on the chelate formation are discussed. Complexes of Cu(II) and Ni(II) have been synthesised and characterised by elemental analysis, electrolytic conductance, IR spectra and magnetic susceptibility measurements. The ligand forms bis-complexes with Cu(II) and Ni(II). The binding sites are oxygen and sulphur atoms.     

Zn 还原过渡金属化合物制备金属粉体的过程

用Zn粉还原过渡金属Fe、Co、Ni和Cu的硫酸盐和硫酸铵复盐溶液，获得了相应金属的纳米粉体.详细研究了此反应的还原过程.用XRD、SEM、TEM和ED等方法对产物进行了表征，发现析出的粉体不同程度上均生成有Zn置换的固溶体. Fe在Zn粒外层生成薄层Fe-Zn固溶体，Ni和Co为粒径分别为7.5 nm和12.1 nm的Zn饱和固溶体， Cu则在外层生成Cu5Zn8的新相.讨论了还原过程的机制，认为和M-Zn电池电动势的驱动力有关.     

Gas Chromatography of Transition Metal Salicylaldimine Complexes

Abstract

The stability and ease of formation of some neutral salicylaldimine transition metal complexes has suggested that they may be gas chromatographed and find analytical applications. Thermal an of some bidentate Ni(II), Cu(II) and Zn(II) salicylaldimine comp has shown them to be thermally stable and volatile. Observations the gas chromatographic separation of some of these chelates is described, their favorable properties allow elution from glass a stainless steel columns with minimal decomposition under favorable conditions.     

Separation of Selected Transition Metal Ions and Divalent Metal Ions by HPLC Using UV-VIS Detection

Abstract

The use of ethylenediaminetetraacetic acid, disodium salt, (pH 3-5) has been investigated as an eluant for the separation and detection of nanogram levels of selected divalent and trivalent metal ions. The effect of pH and eluant concentration upon the retention times and resolution of the system are given and the ability to alter the eluant characteristics to optimize the chromatographic results in different situations will be discussed. The method is less complicated than the method frequently used for transition metal ion determinations which uses a post-column derivitization reagent. This method is applicable to a wider range of metal ions and provides detection limits which are generally within two orders of magnitude of the post-column derivitization method.     

Transition Metal Complexes with Pyrazole Based Ligands

The complex formation of cobalt(II)-, nickel(II) and copper(II) sulphate hydrates with 3,5-dimethyl-1-thiocarboxamidepyrazole (HL) was studied. The influence of the anions on the course of the reaction was also examined, using nickel(II) salts with various anions. Beside the NiSO₄·7H₂O the reaction has been carried out with Ni(OAc)₂, Ni(CF₃COO)₂ and Ni(SCN)₂. Compounds with the following composition were obtained: Co(L)₃, Ni(L)₂ and [Cu(SCN)L]₂. The structure of the ligand and the Co(L)₃ complex was determined by single crystal X-ray analysis, while that of the Ni(L)₂ was solved by analysis of powder diffraction X-ray data. The most probable structure of the copper(II) complex is proposed on the basis of the elemental analyses data, FT-IR spectrometry and magnetic measurement. The thermal decomposition of the complexes was investigated by thermogravimetry, DSC and coupled TG-MS measurements. In the case of the nickel(II) compound, a relatively stable intermediate was detected in the 550-650 K temperature range. The composition of the intermediate, Ni(SCN)(NCS), was determined by FT-IR-spectrometry. This revised version was published online in July 2006 with corrections to the Cover Date.     

New Designs for Phototherapeutic Transition Metal Complexes

In this Minireview, we highlight recent advances in the design of transition metal complexes for photodynamic therapy (PDT) and photoactivated chemotherapy (PACT), and discuss the challenges and opportunities for the translation of such agents into clinical use. New designs for light‐activated transition metal complexes offer photoactivatable prodrugs with novel targeted mechanisms of action. Light irradiation can provide spatial and temporal control of drug activation, increasing selectivity and reducing side‐effects. The photophysical and photochemical properties of transition metal complexes can be controlled by the appropriate choice of the metal, its oxidation state, the number and types of ligands, and the coordination geometry.     

Paper Chromatographic Separation of DMSO Complexes of Metal Ions

Abstract

R_f, values of DMSO complexes of some metal ions in twelve solvent systems are given. The separation of Zn and Hg DMSO complexes from others have been achieved in Water and in n-butyl alcohol respectively by using paper chromatography. Some other possible separations are also reported.     

过渡金属络合物催化乙烯齐聚

综述了乙烯齐聚的最新成果,重点阐述了用于乙烯齐聚的新型催化剂,讨论了烯烃高聚与齐聚催化剂的关系,烯烃高聚与齐聚的反应机理相同,。差别主要在于烯烃插入与β－H消除反应的速率,第IV副族金属络合物主要催化乙烯齐聚,第Ⅲ副族金属主要催化乙烯高聚,改变茂金属催化体系的助催化剂和反应条件可得到齐聚产物,选择体积较小配体的第Ⅷ族金属络合物,有利于β－H消除得到齐聚产物。