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Parent and mixed-ligand cobalt(II) complexes of different compositions were prepared with water, sulfate ion and 1,2-ethanediol as ligands. The magnetic susceptibility data, the IR spectra and the thermoanalytical curves of the complexes were recorded. Oxygen atoms bound by one or two coordinate bonds to the metal ion, or by hydrogen-bonds were observed in the crystals pace.

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Abstract  

The chloro complexes of 2-amino-3-methylpyridine with cobalt(II) and copper(II) have been prepared in ethanolic solution and solid compounds have been isolated. The compounds have stoichiometry ML2Cl2 whereM is Co2+ or Cu2+ and L is 2-amino-3-methylpyridine. Spectral and magnetic studies have been used to obtain information about the environment of the metal ion in these compounds. The compounds have tetrahedral structures. The thermal decomposition of each compound has been studied using thermogravimetry and differential thermal analysis. Thermogravimetry studies show that the cobalt complex forms an intermediate compound before the metal oxide is produced while the copper compound undergoes decomposition with loss of organic ligand and the formation of copper chloride which then decomposes to give an oxide of copper. The enthalpy of reaction for each of the processes has been calculated from the thermal analysis curves.

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Abstract  

Parent and mixed ligand complexes of manganese(II) ion were prepared with water, sulfate ion and 1,2-ethanediol as ligands. The IR spectra and the thermoanalytical curves of the complexes were recorded. Oxygen atoms bound by one or two coordinate bonds to the metal ion, or by hydrogen-bonds in the crystal, were observed. As for the water molecule, ‘crystal’ and ‘monohydrate’ type of 1,2-ethanediol molecules were found, depending on the type of binding of the oxygen atoms.

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Primary aliphatic amine complexes of transition-metal halides

III. Thermal and spectroscopic characterization of solid methylamine complexes of nickel(II) halides

Journal of Thermal Analysis and Calorimetry
Authors: G. Kenessey, B. Carson, J. Allan, T. Wadsten, and G. Liptay

Abstract  

The hexakis(methylamine) complexes of nickel(II)-chloride, -bromide and -iodide have been prepared using-gas phase preparation procedure. The thermal decomposition starts with the release of four moles of the organic ligand. The bis(methylamine) intermediate decomposes in one step to the pure nickel(II) halide in the case of the chloride compound, however one and a half moles of methylamine containing intermediates were identified for the bromide and iodide analogues. The UV/VIS and the far IR spectra of the hexakis complexes show a typical octahedral environment around the central nickel(II) ion.

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The in situ spectroscopic investigation of electrochemical, and especially corrosion processes in iron requires well-characterized reference substances. It has been found that the application of spectroscopic methods alone is not sufficient for the detection of impurities in certain phases. Thermoanalytical methods have therefore additionally been used to detect impurities and to optimize the preparation methods. Infrared and Raman spectra and thermoanalytical data onα-FeOOH,β-FeOOH,γ-FeOOH,δ-FeOOH and on amorphous iron(III) hydroxide sol are reported.

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On the dioximine complexes of transition metals

LXXVII. Formation and thermal decomposition of some complexes NH4[Co(DH)2(SO3)(amine)]·t H2O

Journal of Thermal Analysis and Calorimetry
Authors: J. Zsakó, Cs. Várhelyi, G. Liptay, and A. Borbély-Kuszmann

Twelve new complexes NH4[Co(DH)2(SO3)(amine)]·t H2O (DH 2=dimethylglyoxime) have been synthesized and characterized. Their i.r. spectra show the SO3 to be co-ordinated to the Co atom through the S atom. The thermal decompositions of a series of derivatives of this type have been investigated with a derivatograph. The first process is an endothermic dehydration reaction, occurring in a single stage or in two successive ones. The loss of the crystallization water is followed by another endothermic reaction, without a clear stoichiometry, which is referred to as “deamination”. At higher temperatures, exothermic pyrolysis processes occur. From the TG curves, kinetic parameters have been derived for the dehydration and deamination reactions.

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The thermal decomposition of theα, β andγ- picoline complexes of cadmium were studied by means of TG-DTG-DTA. In connection with the preparation of the complex compounds, it was established that the ligand number was influenced by the reaction medium. The thermal decomposition took place stepwise, and intermediates were formed which could be isolated with a derivatograph by the “freezing-in” method. The structures and properties of these previously unknown compounds were investigated by far-IR spectroscopy and X-ray powder diffraction.

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