The new mixed-ligand complexes of d-electron metals (M(II)=Mn, Ni, Cu) with 2,2'-bipyridine (2-bpy) and mono- or dichloroacetates were prepared as crystalline solids. The general
formulae of the synthetized complexes are: Cu(2-bpy)2(CClH2COO)22H2O, Mn(2-bpy)2(CCl2HCOO)2, M(2-bpy)2(CCl2HCOO)22H2O (M(II)=Ni, Cu). The compounds were characterized by chemical analysis, IR and VIS spectroscopy. Their magnetic, molar conductivity
and thermal properties also were studied. During heating in air complexes decompose via different intermediate products to
metal oxides. A coupled TG-MS system was used to analyse the principal volatile thermal decomposition (or fragmentation) products
of 2,2'-bipyridine-chloroacetato complexes.
Lead(II) 2,2'-bipyridine hexachloroplumba tetetrahydrate was synthesized and investigated by DTA, TG and DTG. IR spectroscopy
and other methods enabled the identification of some of the decomposition products. Comparative studies on the corresponding
chlorides: [Pb(bipy)]Cl2 and [Pb(bipy)3]Cl2, which can be considered as precursors of the hexachloroplumbate, were also undertaken. X-ray measurements enabled the tentative
determination of the crystal structure of [Pb(bipy)]Cl2. Hexachloroplumbate decomposes with the liberation of chlorine, water and organic ligands, and the process is accompanied
by the simultaneous transition of Pb(IV)→Pb(II). Chlorides release only ligands upon heating. Residues comprised always PbCl2.
Authors:L. Tian, N. Ren, J. Zhang, H. Liu, S. Sun, H. Ye, and K. Wu
The two complexes of [Ln(CA)3bipy]2 (Ln = Tb and Dy; CA = cinnamate; bipy = 2,2′-bipyridine) were prepared and characterized by elemental analysis, infrared
spectra, ultraviolet spectra, thermogravimetry and differential thermogravimetry techniques. The thermal decomposition behaviors
of the two complexes under a static air atmosphere can be discussed by thermogravimetry and differential thermogravimetry
and infrared spectra techniques. The non-isothermal kinetics was investigated by using a double equal-double steps method,
the nonlinear integral isoconversional method and the Starink method. The mechanism functions of the first decomposition step
of the two complexes were determined. The thermodynamic parameters (ΔH≠, ΔG≠ and ΔS≠) and kinetic parameters (activation energy E and the pre-exponential factor A) of the two complexes were also calculated.
Complexes of the general formulae Mn(2-bpy)2(CCl3COO)2, Co(2-bpy)2(CCl3COO)2H2O and Ni(2-bpy)2(CCl3COO)22H2O (where: 2-bpy=2,2'-bipyridine) have been prepared and characterized by VIS and IR spectroscopy, conductivity and magnetic measurements.
The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During
heating the complexes decompose via different intermediate products to the oxides Mn3O4, CoO and NiO. A coupled TG-MS system was used to detection the principal volatile products of thermal decomposition and fragmentation
processes of obtained compounds. The principal volatile products of thermal decomposition of complexes are: H2O+, CO2+, Cl2+ and other.
Authors:P. Naumov, V. Jordanovska, O. Grupče, B. Boyanov, and G. Jovanovski
The adducts of Co, Ni, Cu, Zn and Pb saccharinates with 2,2'-bipyridine were synthesized and their thermal behaviour in the 20–1000°C temperature interval in a static air atmosphere was investigated. Regardless of the coordination, the decomposition starts with dehydration and proceeds with removal of the bipyridine ligand(s). The resulting metal(II) saccharinates adopt characteristic two-step decomposition, the first step being the SO2 release. Their stability was found tobe metal-dependent. The thermal decomposition pathways were correlated with the existing structural data about the compounds.
Authors:D. Czakis-Sulikowska and J. Kałużna-Czaplińska
The compounds ML2(NCS)2, (M(II)=Mn, Co), FeL2(NCS)22H2O, NiL3 NCS)23H2O (L=2,2'-bipyridine, 2-bipy) MX2(NCS)22H2O (M(II)=Mn, Fe; X=4,4'-bipyridine, 4-bipy) have been prepared and their IR spectra and molar conductivity studied. The thermal decomposition
of the complexes was studied under non-isothermal conditions in air. During heating the hydrated complexes lose crystallization
water molecules in one or two steps and then decompose via different intermediate compounds to the oxides Mn3O4, Fe2O3, CoO, NiO.
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.
The thermal behavior of[Eu2(BA)6(dmbpy)2] (BA=C7H5O
, benzoate; dmbpy=C12H12N2, 4,4-dimethyl-2,2-bipyridine) and its kinetics were studied under the non-isothermal condition in a static air atmosphere by TG-DTG, IR and SEM methods. Thermal decomposition of [Eu2(BA)6(dmbpy)2] occurred in four consecutive stages at TP 232, 360, 455 and 495°C. The kinetic parameters were obtained from analysis of the TG-DTG curves by Achar and Madhusudanan—Krishnan—Ninan (MKN) methods. The most probable mechanisms for the first stage was suggested by comparing the kinetics parameters.
The complexes of [Sm(o-MOBA)3bipy]2·H2O and [Sm(m-MOBA)3bipy]2·H2O (o(m)-MOBA = o(m)-methoxybenzoic acid, bipy-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, XRD and
molar conductance, respectively. The thermal decomposition processes of the two complexes were studied by means of TG–DTG
and IR techniques. The thermal decomposition kinetics of them were investigated from analysis of the TG and DTG curves by
jointly using advanced double equal-double steps method and Starink method. The kinetic parameters (activation energy E and pre-exponential factor A) and thermodynamic parameters (ΔH≠, ΔG≠ and ΔS≠) of the second-step decomposition process for the two complexes were obtained, respectively.