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Abstract  

New dihydrazinium divalent transition metal trimellitate hydrates of empirical formula (N2H5)2M(Html)2·nH2O, where n = 1 for M = Co or Ni, and n = 2 for M = Mn, Zn, or Cd (H3tml = trimellitic acid), and monohydrazinium cadmium trimellitate, [(N2H5)Cd(Html)1.5·2H2O] have been prepared and characterized by physico-chemical methods. Electronic spectroscopic, and magnetic moment data suggest that Co and Ni complexes adopt an octahedral geometry. The IR spectra confirm the presence of monodentate carboxylate anion (Δν = νasy(COO) − νsym(COO) > 190 cm−1) and coordinated N2H5 + ion (νN–N 1015 − 990 cm−1) in all the complexes. All the complexes undergo endothermic decomposition eliminating CO2 in the temperature region 200–250 °C, followed by exothermic decomposition (in the range of 500–570 °C) of organic moiety to give the respective metal carbonate as the end products except nickel and cobalt complexes, which leave respective metal oxides. X-ray powder diffraction patterns reveal that Ni and Co complexes are isomorphous as are those of, Zn(II) and Cd(II) of the type, (N2H5)2M(Html)2·2H2O.

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Abstract  

New divalent transition metal 3,5-pyrazoledicarboxylate hydrates of empirical formula Mpz(COO)2(H2O)2, where M=Mn, Co, Ni, Cu, Zn and Cd (pz(COO)2=3,5-pyrazoledicarboxylate), metal hydrazine complexes of the type Mpz(COO)2N2H4 where M=Co, Zn or Cd and Mpz(COO)2 nN2H4H2O, where n=1 for M=Ni and n=0.5 for M=Cu have been prepared and characterized by physico-chemical methods. Electronic spectroscopic data suggest that Co and Ni complexes adopt an octahedral geometry. The IR spectra confirm the presence of unidentate carboxylate anion (Δν=νasy(COO)–νsym(COO)>215 cm–1) in all the complexes and bidentate bridging hydrazine (νN–N=985–950 cm–1) in the metal hydrazine complexes. Both metal carboxylate and metal hydrazine carboxylate complexes undergo endothermic dehydration and/or dehydrazination followed by exothermic decomposition of organic moiety to give the respective metal oxides as the end products except manganese pyrazoledicarboxylate hydrate, which leaves manganese carbonate. X-ray powder diffraction patterns reveal that the metal carboxylate hydrates are isomorphous as are those of metal hydrazine complexes of cobalt, zinc and cadmium.

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Abstract  

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.

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, C , Rogozea , EA . Thermal behavior and spectroscopic studies of complexes of some divalent transitional metals with 2-benzoil-pyridilizonicotinoylhydrazone . J Therm Anal Calorim . 2010 ; 101 : 987 – 996 . 10.1007/s10973-009-0560-z

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Journal of Thermal Analysis and Calorimetry
Authors: C. Bâtiu, I. Panea, L. Ghizdavu, L. David, and S. Ghizdavu Pellascio
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Abstract  

The thermal behaviours of the Ti(II), Mn(II), Fe(II), Ni(II), Cu(II) and Zn(II) complexes of triethanolamine were studied by means of thermogravimetry, differential thermogravimetry, differential thermal analysis infrared spectrophotometry and elemental analysis. The sequence of thermal stability of the metal complexes, determined by using the initial decomposition temperature, was found to be Ti(II)≅Mn(II)>Fe(II)>Ni(II)>Zn(II)>Cu(II). Some of the kinetic parameters, such as the activation energy and order of reaction for the initial decomposition reaction, were calculated and the relationship between the thermal stability and the chemical structure of the complexes is discussed.

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Abstract  

Several complex salts of the general formula [M(II) (bipy)x(H2O)y]PbCl6 (where x=2–3, y=0–2 and M=Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were synthesized and investigated by DTA, TG and DTG. Some of the decomposition products were identified by IR spectroscopy and other methods. The compounds decompose with the liberation of water (in the case of hydrates), chlorine (sometimes causing chlorination of organic fragments), organic molecules (sometimes chlorinated) and sometimes hydrogen chloride. The residues comprise metal(II) chlorides and PbCl2.

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