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Abstract  

A novel complex [Ni(H2O)4(TO)2](NO3)2·2H2O (TO = 1,2,4-triazole-5-one) was synthesized and structurally characterized by X-ray crystal diffraction analysis. The decomposition reaction kinetic of the complex was studied using TG-DTG. A multiple heating rate method was utilized to determine the apparent activation energy (E a) and pre-exponential constant (A) of the former two decomposition stages, and the values are 109.2 kJ mol−1, 1013.80 s−1; 108.0 kJ mol−1, 1023.23 s−1, respectively. The critical temperature of thermal explosion, the entropy of activation (ΔS ), enthalpy of activation (ΔH ) and the free energy of activation (ΔG ) of the initial two decomposition stages of the complex were also calculated. The standard enthalpy of formation of the new complex was determined as being −1464.55 ± 1.70 kJ mol−1 by a rotating-bomb calorimeter.

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Abstract  

The chloro complexes of cobalt, nickel and copper with 3-phenylpyridine were prepared in ethanolic solution from which solid compounds were isolated. The cobalt and copper complexes have stoichiometry M2LCl4 while the nickel complex has stoichiometry NiLCl2. The suggested structure for the cobalt and copper complexes is tetrahedral, while for the nickel complex it is octahedral. Thermal analysis studies show that the cobalt and copper complexes form intermediate complexes before their metal oxides are produced. The nickel complex also forms an intermediate complex and then nickel chloride before the nickel oxide is obtained.

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Journal of Thermal Analysis and Calorimetry
Authors: O. Çakırer, E. Eker, Ü. Ergun, E. Gökçınar, L. Tatar Yıldırım, H. Dal, and O. Atakol

Abstract  

Two ONNO type naphtaldehyde derivative Schiff base compounds were reduced and two symmetric phenol-amine ligands containing naphthalene groups were obtained; bis-N,N′[(2-hydroxy-1-naphtyl) methyl]-1,3-propanediamine (NAFLH) and bis-N,N′[(2-hydroxy-1-naphtyl) methyl]-2,2′-dimetyhyl-1,3-propanediamine (NAFLDMH). Homotrinuclear Ni(II) complexes of these ligands were prepared. The solid-state molecular structures of representative nickel complex of NAFLDMH were determined using single crystal X-ray diffraction analysis. The terminal Ni(II) ions were found to be situated in between the donor atoms of the organic ligand. The central Ni(II) ion was observed to be bonded via two different μ-bridges. The phenolic oxygens and carboxylate ion were seen to form two different μ-bridges. TG analysis proved that the compounds have different thermal characteristics than those cited in literature. The complexes showed extreme exothermic degradation reactions in inert atmosphere. The complexes are ruptured with a two stepped exothermic reaction which appears huge heat over 300 °C. The heat appeared in O2 atmosphere is observed to be higher than the heat appeared in inert atmosphere. Revealed heat is observed to be higher than the conventional explosive materials.

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Abstract  

Cobalt, nickel and zinc dicarboxylate complexes containing neutral hydrazine as bridged bidentate ligand of the type MX(N2H4)n where n=1 for X=OOCCH2COO and n=2 for X=OOCCH2COO, OOCCH2CH2COO and OOCC(CH2)CH2COO have been prepared by aqueous reactions. These complexes have been characterized by analytical, spectral and thermal studies. The electronic spectra coupled with magnetic moments of cobalt and nickel complexes suggest these complexes are of high-spin variety with octahedral geometry. Infrared spectra indicate the bridging bidentate nature of hydrazine moieties present in both mono-hydrazine and bis-hydrazine complexes and the dicarboxylate ions coordinate to the metal as bidentate ligand through the monodentate coordination of each carboxylate ion. However, in the mono-hydrazine metal malonates both carboxylate ions act as bridged ligands. Simultaneous TG-DTA curves of all the complexes in air resulted in the formation of respective metal oxide as final residue at low temperatures (300–400C). These complexes decompose either in single step or decompose through respective metal carboxylate intermediates. In most of the cases the decompositions are exothermic while in some cases they are violently exothermic. The thermal degradation of these complexes in nitrogen atmosphere also gives the respective metal oxide as the final residue.

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Journal of Thermal Analysis and Calorimetry
Authors: Gurdip Singh, A. K. Shrimal, Inder Pal Singh Kapoor, Chandra Prakash Singh, Dinesh Kumar, and Manan S. Mudi

observed for zinc, copper, and nickel complexes, respectively ( Table 2 ). Corresponding to this first step mass loss, DTG peaks are obtained. Although the thermolysis is done up to the temperature of 893 K, the residue left is more than the corresponding

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–Metzger (HM) and MacCallum–Tanner (MT) [ 6 – 9 ]. Experimental The nickel complexes were synthesized as per the procedure reported in the literature [ 10 ]. Nickel content in the complexes was determined by gravimetry [ 11 ]. The

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.96 The value of reaction order, n , is around 1 for decomposition of all the complexes synthesized. Based on the TG traces, it can be elucidated that nickel complex is thermally the least stable out of all the complexes, which is in accordance with the

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concerning antiviral activity [ 3 – 5 ]. The importance of the complexes with bicyclams derived from the fact that they are active against both HIV-1 and HIV-2 [ 6 ]. Among these, the zinc and nickel complexes with the some bicyclams are slightly more

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et al. [ 2 ] have reported the formation of ultrafine metallic copper wires by the thermal decomposition of tris(ethylenediamine)copper(II) halides. Syntheses of nano NiO or Ni by the thermal decomposition of nickel complexes have also been reported

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( Fig. 5 ) consists of the d – d type bands from different ions of the two metals with their different symmetry and the CT transition bands. A broad band at 474 nm corresponds to d – d transitions of a nickel ion, which is typical of nickel complexes

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