26 research outputs found

    (Carbonato-κ2 O,O′)bis­(di-2-pyridyl­amine-κ2 N,N′)cobalt(III) bromide

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    In the title compound, [Co(CO3)(C10H9N3)2]Br, a distorted octa­hedral coordination of the CoIII atom is completed by four N atoms of the two chelating di-2-pyridyl­amine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridyl­amine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C 2 symmetry, is connected to the bromide ion via an N—H⋯Br− hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N—H⋯O inter­actions about an inversion centre. A set of weaker C—H⋯O and C—H⋯Br− inter­actions connect the dimers into a three-dimensional network

    Synthesis, thermal analysis, and spectroscopic and structural characterizations of zinc(II) complexes with salicylaldehydes

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    In this study, three new zinc(II) complexes with 5-substituted salicylaldehyde ligands (X-saloH) (X = 5-chloro, 5-nitro and 5-methyl) with the general formula [Zn(X-salo)(2)(CH3OH)n], (n = 0 or 2) were synthesized. An octahedral geometry was found for both the complexes [Zn(5-NO2-salo)(2)(CH3OH)(2)] and [Zn(5-Cl-salo)(2)(CH3OH)(2)] by single-crystal X-ray diffraction analysis. These complexes were characterized also by spectroscopy (IR and H-1-NMR). Simultaneous TG/DTG-DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed by applying both the isoconversional Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahira-Sunose (KAS) methods

    Synthesis, thermal analysis, and spectroscopic and structural characterizations of tetranuclear nickel(II) cubane-type clusters with 2-hydroxybenzaldehydes or 2-hydroxyphenones

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    In this study, three novel tetranuclear nickel(II) cubane-type clusters with the general formula [Ni-4(L)(4)(mu(3)-CH3O)(4)(CH3OH)(4)] [L: the anion of 5-methyl-2-hydroxybenzaldehyde (1), 2-hydroxypropiophenone (2), and 2-hydroxybenzophenone (3)] were synthesized and characterized by single-crystal X-ray diffraction analysis. The crystal structure of each compound contains a tetranuclear cubane core [Ni4O4] based on an approximately cubic array of altering nickel and oxygen atoms with intracluster metal-metal separations of 3.04-3.14 . Each Ni(II) atom is surrounded by two oxygen atoms from the ligand (L) and by the mu(3)-CH3O oxygen atom that bridges three Ni atoms of the cubane core. The coordination sphere of Ni is completed with one methanol molecule and making six-coordinate with a distorted octahedral geometry. These complexes were characterized also by spectroscopy (IR and UV-Vis). Simultaneous TG/DTG-DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed for the first step of complex (3), since only this verifies the requirement of applying an isoconversional method like Kissinger-Akahira-Sunose (KAS). For this step, we found the average value E (a) = 107.8 +/- A 4.5 kJ mol(-1)
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