Synthesis,Identification and Thermal Decomposition of Double Sulfates of Mn,Cu and Cd with Benzylammonium

On evaporation of an aqueous mixture of M(II) sulfate (M(II) = Mn, Co, Ni, Cu, Zn or Cd) and benzylammonium sulfate in a molar ratio of 1:2 at room temperature in the presence of sulphuric acid, double sulfates of only Mn, Cu and Cd were obtained. The stoichiometries of the compounds were determined by means of elemental and TG analysis. It was concluded that these compounds have the same general formula: M(C₆ H₅ CH₂ NH₃ )₂ (SO₄ )₂ ×4H₂ O. These compounds have the same stoichiometry as that of the corresponding double sulfates with ethanolammonium cation, but have different crystal structures. The thermal decompositions of the investigated compounds in the temperature range from ambient temperature up to 1000°C take place in a similar way, in three well-differentiated stages, but with different pathways in the second and third stages. Metal oxides were obtained as final products. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Thermal Decomposition of Mixed 2,4'-bipyridine-oxalato Complexes With Mn(II), Co(II), Ni(II) and Cu(II)

The mixed 2,4'-bipyridine-oxalato complexes of the formulae M(2,4'-bipy)₂ C₂ O₄ 2H₂ O (M (II)=Mn, Co, Ni, Cu; 2,4'-bipyridine=2,4'-bipy or L ; C₂ O^2– ₄ =ox) have been prepared and characterized. IR data show that the 2,4'-bipy coordinated with these metals(II) via the least hindered (4')N atom; that oxalate group acts as bidentate chelating ligand. Room temperature magnetic moments are normal for the orbital singlet states. The thermal decomposition of these complexes was investigated by TG, DTA and DTG in air. The endothermic or exothermic character of the decomposition of ML₂ (ox)2H₂ O was discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal and Infrared Study of Desorption of Pyridine and Pyridine Derivatives from Ni-exchanged Montmorillonite

Thermal analysis (TG, DTG) and infrared absorption spectra were used to study desorption of pyridine (py), 4-methylpyridine (4-Mepy) and 4-ethylpyridine (4-Etpy) from Ni(II)-exchanged montmorillonite (Ni-MMT). It is shown that the bonds between the derivatives of pyridine (R-py) and the montmorillonite exhibit predominantly Lewis acid character. The thermal stability of studied samples and the total amounts of R-py inserted in the porous structure of Ni-MMT increase in the following sequence: py/Ni-MMT<4-Mepy/Ni-MMT<4-Etpy/Ni-MMT, i. e. the influence of the substituent on the pyridine ring is evident. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Decomposition Kinetics of the Zn(II) Complex with Norfloxacin in Static Air Atmosphere

The thermal decomposition of Zn[NFA]₂5H₂O (NFA=C₁₆H₁₈FN₃O₃, norfloxacin) and its kinetics were studied under non-isothermal conditions in air by TG-DTG and DTA methods. The intermediate and residue for each decomposition were identified from the TG curve. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The possible reaction mechanisms were investigated by comparing the kinetic parameters. The kinetic equation for the second stage can be expressed as d/dt=Aexp(–E/RT)(1–).This revised version was published online in November 2005 with corrections to the Cover Date.     

Thermal Behaviour of the N-donor Adducts of Metal Saccharinates. II. 1,10-phenanthroline saccharinato complexes of Co(II), Ni(II), Cu(II), Zn(II) and Pb(II)

Adducts of Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) saccharinates with 1,10-phenathroline were synthesized and their thermoanalytical (TG, DTG and DTA) curves in the 20–1000°C temperature interval and static air atmosphere were recorded. The complexes are best represented as M(C₁₂H₈N₂)_x(C₇H₄NO₃S)₂⋅yH₂O (x=2, 2, 2, 2 and 1; y=1, 1, 2, 1 and 2 for M=Co, Ni, Cu, Zn and Pb, respectively). The decomposition of the compounds regularly started with dehydration, followed by loss of the phenanthroline ligand(s). The structures of the Cu and Pb complexes are notably different from other compounds. FTIR spectra of the title compounds in the region of the OH, CO and SO₂ stretching vibrations were also studied. The pronounced similarity of the spectra of Co, Ni and Zn adducts indicates possible isomorphism among them. This revised version was published online in July 2006 with corrections to the Cover Date.     

金刚乙胺水杨醛Schiff碱锌(Ⅱ)配合物的合成、表征、晶体结构和热分解动力学研究

A Zinc(Ⅱ) complex [ZnCl₂(HL)₂] with Schiff base HL derived from rimantadine and salicylaldehyde was synthesized and characterized by elemental analysis, infrared spectra, ¹H NMR spectra,molar conductance, ultraviolet and visible spectra, thermal analysis. Its structure was determined by single crystal X-ray diffraction method. The complex, C₃₈H₅₀Cl₂N₂O₂Zn, crystallizes in the orthorhombic system, space group Aba2 with a=1.381 7(3), b=2.275 0(5), c=1.145 0(2) nm, V=3.599(1) nm³, Z=4, M_r=653.79, F(000)=1 496, D_c=1.301 kg·m^-3, μ(Mo Kα)=0.866 mm^-1. The kinetic parameters were obtained from the analysis of TG curve by integral methods. The functions of thermal decomposition reaction mechanism are: F(α)=[1-(1-α)^1/3]², and kinetic compensation effect equation lnA=0.019 1E-0.142 7. CCDC: 253297.     

Kinetics and Mechanism of the Thermal Decomposition of M(NO3)2·nH2O (M=Cu,Co, Ni)

This paper presents the results of simultaneous DTA-TG-DTG and DSC studies on the thermal decomposition of Cu(NO3)2·3H2O, Co(NO3)2·6H2O and Ni(NO3)2·6H2O in an air atmosphere. The mechanism and enthalpies of the investigated processes were determined, as well as the kinetic parameters of the processes run under non-isothermal conditions by means of Kissinger's method. The dependence of the activation energy on the ionic radius of the cations building up the crystal lattices of the investigated compounds was also studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Thermal Decomposition of the Macrocyclic Dinuclear Ni(II) Complex

Crystal of the complex Ni₂L (ClO₄)₂ was obtained by reaction of Ni(ClO₄)₂ and macrocyclic ligand H₂L, where L^2– is the dinucleating macrocycle with two 2,6-di(aminomethyl)-4-methyl phenolate entities combined by the same two lateral chains, –(CH₂)₂–NH–(CH₂)₂–, at the amino nitrogens. The thermal decomposition processes of the title complex were studied in a dynamic atmosphere of dry argon using TG-DTG. The kinetic analysis of the first and second thermal decomposition steps were performed via the TG-DTG curves, and the kinetic parameters were obtained from analysis of the TG-DTG curves with integral and differential methods. The most probable kinetic function was suggested by comparison of the kinetic parameters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Thermal Behaviour of the N-donor Adducts of Metal Saccharinates III. Imidazole saccharinates of Co(II), Ni(II) and Cd(II)

The complexes [M(HIm)₄(H₂O)₂](sac)₂ (M=Co, Ni) and [Cd(HIm)₂(sac)₂]₂ with saccharin (sac) and imidazole (HIm) were synthesized and their thermal (TG, DTG and DTA) behaviour in the interval from room temperature up to 1000°C in a static air atmosphere was investigated. Irrespectively of whether the deprotonated saccharinato residues are present as ligands or ions or both as ligands and ions, the anhydrous complexes regularly decompose in two stages. The thermal data of 16 saccharinato complexes (including the title compounds) were correlated with the respective structural data. The general thermal stability order of the saccharinato complexes can be represented as: Pb(II)<Zn(II)<Co(II)Ni(II)<Cd(II) (the stability of the Cu saccharinates depends on the particular compound) and is dictated by several structural factors, e.g. metal ionic radii, participation of the water in the coordination sphere of the metal and other structural characteristics. This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization and TG-MS studies of lactato and bipyridine-lactato complexes of Co(II) and Ni(II)

Two lactates and four new mixed ligand complexes with formulae Co(lact)₂·2H₂O, Ni(lact)₂·3H₂O, Co(4-bpy)(lact)₂, Co(2,4'-bpy)₂(lact)₂, Ni(4-bpy)(lact)₂·2H₂O and Ni(2,4'-bpy)₂(lact)₂ (where 4-bpy=4,4'-bipyridine, 2,4'-bpy=2,4'-bipyridine, lact=CH₃CH(OH)COO^-) were isolated and investigated. The thermal behaviour of compounds was studied by thermal analysis (TG, DTG, DTA). In the case of hydrated complexes thermal decomposition starts with the release of water molecules. The compounds decompose at high temperature to metal(II) oxides in air. A coupled TG-MS system was used to analyse the principal volatile products of thermolysis and fragmentation processes of obtained complexes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis, Characterization and Thermal Decomposition of Hydroxylammonium Uranyl Acetate

The synthesis of hydroxylammonium uranyl acetate is described. The identity of the synthesized compound was confirmed by chemical and infrared analysis. The intermediates and final products of the thermal decomposition were identified by means of thermogravimetric analysis, differential thermal analysis and X-ray diffraction. The thermal decomposition of hydroxylammonium uranyl acetate involves several steps. Two of them are due to decomposition of this compound to UO₂ via UO₂(CH₃COO)₂, and the third to the partial oxidation of UO₂ to UO₃ and the formation of U₂O₈ in the solid state at higher temperature.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis, Crystal Structure and Kinetic Mechanism of Thermal Decomposition of a Zinc(II) Complex with N-Salicylidene-p-toluidine

1 INTRODUCTION Over the past decades, considerable attention has been devoted to the synthesis, characterization and property studies of Schiff bases and their com- plexes because of their potential and developed appli- cations in the fields of conducting and magnetic ma- terials, dyes, non-linear optics, catalysis, analytical chemistry, biochemical research, agriculture and so on[1～7]. A large number of reports are available in the chemistry and biologic activities of transition metal co…     

Non-isothermal Decomposition Kinetics of Complex of Co(III), Ni(II) with O,O'-dialkyldithiophosphates and Adducts of Ni-complex with Pyridines

Thermal behaviour of tri(O,O'-diisopropyldithiophosphate)cobalt(III), Co(dptp)₃ and bis (O,O'-diethyldithiophosphate)nickel(II), Ni(detp)₂ and its adducts with pyridine, Ni(detp)₂(py)₂ or 4-methylpyridine, Ni(detp)(mpy)₂ in a dynamic nitrogen atmosphere was investigated by TG-DTG and DSC techniques, which showed a medium endothermic peak for the evolution process of pyridine(or 4-methylpyridine) and a strong exothermic peak for that of O,O'-diethyldithiophosphate. The thermal stability and decomposition patterns for these compounds were compared and interpreted in terms of structural features such as bond character and steric effects. The kinetic parameters and mechanisms of every decomposition stage involved for all these complexes were obtained employing the non-isothermal kinetic analysis method suggested by Malek et al., which showed the kinetics mechanism for pyrolysis of pyridine(or 4-methylpyridine) is an S-B empirical model with lower activation energy, while that of O,O'-dialkyldithiophosphate is a diffusion model. These results are in accord with the fact that two ligands are of different type. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and Thermal Properties of 4,4'-bipyridine Adducts of Mn(II), Co(II), Ni(II) and Cu(II) Monochloroacetate

The complexes with the empirical formula M(4-bipy)(ClCH₂COO)₂ ×nH₂O (where: 4-bipy=4,4'-bipyridine, L=ClCH₂ COO^–, M (II)=Mn, Co, Ni, Cu) were prepared and characterized via the IR and electronic (VIS) spectra and conductivity measurements. Thermal decomposition of these compounds was studied. During heating in air dehydration processes occur. The anhydrous compounds decompose at high temperature to oxides. The principal volatile mass fragments correspond to: H₂O, CO₂, CH₃Cl, HCl, Cl₂ and other. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preparation,Characterization and Solid State Thermal Studies of Cadmium(II) Squarate Complexes ofhane-1,2-diamine and its Derivatives

[CdL₃]C₄O₄ [L=ethane-1,2-diamine (en)], [CdL₂(H₂O)₂]C₄O₄ [L=N-methylethane-1,2-diamine (meen), N-ethylethane-1,2-diamine (eten), N-propylethane-1,2-diamine (pren), propane-1,2-diamine (pn) and N-methylpropane-1,2-diamine (ibn)] and [CdL₂(C₄O₄)] [L=N-isopropylethane-1,2-diamine (ipren)] have been synthesized by the addition of the respective diamine to finely powdered CdC₄O₄×₂H₂O and their thermal studies have been carried out in the solid state. [Cd(en)₃]C₄O₄ upon heating loses two molecules of diamine in two overlapping steps yielding Cd(en)C₄O₄ which upon further heating transforms to unidentified products. The diaquabis(diamine) species, [CdL₂(H₂O)₂]C₄O₄, show thermally induced deaquation-anation reaction in the solid state and thereby produce [CdL₂(C₄O₄)], which reverts on exposure to humid atmosphere (RH =90%) for 20–24 h. All the squarato bis(diamine) species, [CdL₂(C₄O₄)], on pyrolysis in the solid state transform to unidentified products through the formation of intermediates, CdL_1.5C₄O₄, (L=meen, pren and ipren), CdLC₄O₄ (L=meen, en, pren, ipren, pn and ibn) and CdL_0.5C₄O₄ (L=eten, pn and ibn). However, amongst the intermediates only the mono diamine species, CdLC₄O₄ can be isolated in pure form and the pyrolytic process is the only way to synthesize them. The monodiamine species can be stored in a desiccator as well as in an open atmosphere and proposed to have a polymeric structure. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.     

Thermal, spectral and magnetic characterization of Co(II), Ni(II) AND Cu(II) 4-chloro-2-nitrobenzoates

Physico-chemical properties of 4-chloro-2-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono- and trihydrates with a metal ion to ligand ratio of 1:2. All analysed 4-chloro-2-nitrobenzoates are polycrystalline compounds with colours depending on the central ions: pink for Co(II), green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293–523 K, because it was found that on heating in air above 523 K 4-chloro-2-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step and anhydrous compounds are formed. The final products of their decomposition are the oxides of the respective transition metals. From the results it appears that during dehydration process no transformation of nitro group to nitrite takes place. The solubilities of analysed complexes in water at 293 K are of the order of 10^–4–10^–2 mol dm^–3. The magnetic moment values of Co²⁺, Ni²⁺ and Cu²⁺ ions in 4-chloro-2-nitrobenzoates experimentally determined at 76–303 K change from 3.89 to 4.82 μ_B for Co(II) complex, from 2.25 to 2.98 μ_B for Ni(II) 4-chloro-2-nitrobenzoate, and from 0.27 to 1.44 μ_B for Cu(II) complex. 4-chloro-2-nitrobenzoates of Co(II), and Ni(II) follow the Curie–Weiss law. Complex of Cu(II) forms dimer.     

Amino-Modified Silicate Xerogels Complexed with Cu(II) as Catalyst Precursors. Coordination State and Thermal Decomposition

The sol-gel process is a useful method for preparing two series of organically and co-ordinately modified xerogels of the types [CuN _n ]·N _5–n ·5xSiO_4/2 (n < 4) and [Cu(N–N)_n]·(N–N)_2–n ·2x SiO_4/2(n 2), where N = NH₂(CH₂)₃ SiO_3/2, N–N = NH₂(CH₂)₂NH·(CH₂)₃SiO_3/2 and x = [SiO_4/2]/[N] or [SiO_4/2]/[N–N]. The amino groups in the materials are coordinately active and participate partly in the coordination sphere of Cu(II) ions. The composition of the coordination sphere can be varied with the SiO_4/2 content and also as a result of the thermal decomposition of the organic residues at higher temperatures.Because the xerogel materials are considered to be catalyst precursors, this study is focused on their coordination and thermal properties. The prepared xerogels, such as silica, aminated silicates with N and N–N, as well as those entities complexed with Cu(II), were characterised by FT-IR spectroscopy. During gelation and thermal decomposition the materials were analysed by electron paramagnetic resonance (EPR) spectroscopy. The xerogels were additionally studied by UV-Vis absorption spectroscopy. The gaseous products of the thermal decomposition of these materials in an Ar atmosphere were investigated by the use of FT-IR spectroscopy coupled with TG and DTG thermal analysis. These data were complemented by temperature-programmed decomposition (TPDec) in a 2% O₂ + 98% Ar stream coupled with quadrupole mass spectroscopy.     

Synthesis and Characterization of Ni(II), Cu(II), Zn(II) and Cd(II) Complexes of a New Vic-Dioxime Ligand

In this study, 1,2-dihydroxyimino-3,7-di-aza-9,10-O-α-methyl benzal decane (LH₂) was synthesized starting from 1,2-O-α-methyl benzal-4-aza-7-amino heptane (RNH₂) and antichloroglyoxime. With this ligand, complexes were synthesized using Ni(II) and Cu(II) salts with a metal:ligand ratio of 1:2. However, the reaction of the ligand with salts of Zn(II) and Cd(II) gave products with metal:ligand ratio of 1:1. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C- and ¹H-NMR spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Synthesis, Characterization, Thermal Decomposition Mechanism and Non-Isothermal Kinetics of the Pyruvic Acid-Salicylhydrazone and Its Complex of Praseodymium(III)

IntroductionHydrazonesactasherbicides,insecticides,nemato cides ,rodenticidesandplantgrowthregulators.Theyshowspasmolyticactivity ,hypotensiveactionandactivityagainstleukaemia,sarcomasandothermalignantneoplasm .1Rareearthelementshavestrongbiologicaleffectandmanycom plexesofrareearthshaveallkindofmedicinalactivities.2 Aseriesof 2 oxopropionyl(pyridine 4 fomyl)hydrazonewithrareearthscomplexeswassynthesizedbyYangandtheEucom plexshowedacertainanticanceractivity .3Therearethreeradicalsinthepyru…