Some Tribenzyl Tin(IV) Complexes with Thiohydrazides and Thiodiamines. Synthesis,characterization and thermal studies

Tribenzyl tin(IV) chloride complexes of morpholine N-thiohydrazide (L¹), aniline-N-thiohydrazide (L²),N-(morpholine-N-thio)-1,3-propanediamine (L³) and (aniline-N-thio)-1,3-propanediamine (L⁴) of the type (C₆H₅CH₂)₃Sn(L)Cl (where L=L¹, L², L³ and L⁴) have been synthesised in dioxane and in H₂O and acetone mixture. These were characterized by C,H,N-analysis, UV, IR and ¹HNMR spectral studies. In both the complexes ligands act as bidentate, coordinating through sulphur and terminal nitrogen. The complexes are 1:1 metal ligand complexes. Various thermodynamic parameters have been calculated for the decomposition steps using TG/DTA curves in air as well as nitrogen atmosphere. This revised version was published online in July 2006 with corrections to the Cover Date.     

热分析技术在药物研究中的应用

本文简要介绍了热分析技术在药学领域中的重要性及其应用。由于热分析技术具有试样微量化、快速简便、不用分离试样、不用溶剂、适用范围广、曲线易于解析等优点,在药学研究和药品质量检验等方面,热分析技术将发挥更重要的作用。     

Pressure induced isostructural metastable phase transition of ammonium nitrate

The energetic material ammonium nitrate (AN, NH(4)NO(3)) has been studied under both hydrostatic and nonhydrostatic conditions using diamond anvil cells combined with micro-Raman spectroscopy and synchrotron X-ray powder diffraction. The refined powder X-ray data indicates that under hydrostatic conditions AN-IV (orthorhombic, Pmmn) is stable to above 40 GPa. In one nonhydrostatic compression experiment a volume collapse was observed, suggesting an isostructural phase transition to a "metastable" phase IV' between 17 and 28 GPa. The structures of phase IV and IV' are similar with the subtle difference in the hydrogen-bonding network; that is, a noticeably shorter N1···O1 distance seen in phase IV'. This hydrogen bond has a significant component along the b-axis, which proves to be the most compressible until cell axis over the entire pressure range. It is likely that the shear stress of the nonhydrostatic experiment drives the phase IV-to-IV' transition to occur. We compare the present isotherms of phase IV and IV' in both static and nonhydrostatic conditions with the previously obtained Hugoniot and find that the nonhydrostatic isotherm approximately matches the Hugoniot. On the basis of this comparison, we conjecture that a chemical reaction or phase transition may occur in AN under dynamic pressure conditions at 22 GPa.     

Application of thermal analysis in a phase composition study on by-product from semi-dry flue gas desulfurization system

DTA, TG and XRD methods were used for the determination of by-product - obtained during flue gas desulfurization by means of introduction of dehydration - resisting sludge from water decarbonization system. Analysis results enabled the development and application of sludge utilization technology by means of semi-dry flue gas desulfurization in 'Siersza' power plant. This revised version was published online in July 2006 with corrections to the Cover Date.     

The decomposition of edta-gel precursors in the production of BSCCO superconductors

The decomposition of EDTA gel precursors for BSCCO superconductor manufacture has been studied using STA (TG/DTA) and dilatometry in conjunction with FTIR. The thermoanalytical data are discussed in relation to the sequence of phase formation necessary for the production of the 2223 BSCCO superconducting phase. The effects of substitution of Pb for Bi on the temperatures of formation of the superconducting phases is also discussed. STA has also been carried out under varying oxygen partial pressures to determine the effects of oxygen pressure on the formation and decomposition of the phases involved in the production of the 2223 compound.     

Thermal Decomposition of Strontium and Barium Malonates

The thermal decomposition of strontium and barium malonates has been studied isothermally and non-isothermally employing simultaneous TG-DTG-DTA, DSC, XRD and IR spectroscopic techniques. DSC of these malonates has been recorded both in oxygen and nitrogen atmospheres. The decomposition is a single step process and the end product formed is carbonate. The energy of activation and frequency factor values for the decomposition of strontium malonate are 547 kJ mol⁻¹ and 10⁴¹ s⁻¹ respectively. The activation energy and frequency factor values for isothermal dehydration of barium malonate sester-hydrate are 57–111 kJ mol⁻¹ and 10⁷–10¹² s⁻¹ respectively and the corresponding values for decomposition from DSC are 499.5 kJ mol⁻¹ and 10⁴⁴ s⁻¹ respectively. The higher thermal stability of strontium malonate as compared to that of barium salt is ascribed to its being anhydrous so that decomposition proceeds without restructuring. Their thermal stabilities have also been compared with that of respective oxalate salts. This revised version was published online in July 2006 with corrections to the Cover Date.     

Microgravimetric Apparatus for Sulfidation in Pure Sulfur Vapour at High Temperatures

The mechanism of thermal decomposition of the metal complexes of sulphamethoxazole (SMZ) viz: [Ag(SMZ)H₂O], [Cd(SMZ)₂(H₂O)₂], [VO(SMZ)₂(H₂O)₂], [UO₂(SMZ)₂]H ₂O, [Hg(SMZ)2(H2O)₂] and [Co(SMZ)2(H2O)₂]H₂O has been accomplished on the basis of TG, DTG and DTA studies. The mechanism of thermal decomposition of these complexes conforms to the stoichiometry of the complexes based on elemental analysis.This revised version was published online in November 2005 with corrections to the Cover Date.     

ZnAc2·2H2O在空气中的热分解动力学研究

用TG/DTA,DSC和XRD技术研究了固态物质ZnAc2.2H2O在空气中的热分解过程.结果表明,ZnAc2.2H2O在空气中发生两步分解,其失重率与理论计算失重率相符.XRD结果表明,ZnAc2.2H2O分解的最终产物为ZnO.用Friedman法和Flynn-Wall-Ozawa(FWO)法求得分解过程的活化能E,并通过多元线性回归方法给出了可能的机理函数.ZnAc2.2H2O在空气中两步分解的活化能分别为119.82和66.82kJ/mol.     

Kinetics of Lisinopril degradation in solid phase

Summary The kinetics of degradation of lisinopril (LIS) in solid phase in presence of humidity at 343, 353, 358 and 363 K has been investigated. Changes of the LIS concentration were followed by an HPLC method with UV detection. The thermodynamic parameters at 293 K of degradation of LIS in solid phase E_a (kJ/mol) = 166 ± 47; H*(kJ/mol) = 163 ± 48; S*(J/(K × mol)) = 99 ± 135 for RH = 76.4% have been calculated. Identification of the product of LIS degradation in solid phase was carried out by HPLC-MS. Diketopiperazine derivative of LIS was the major product of its decomposition in the presence of humidity.     

Temperature‐induced conformational transition of bovine serum albumin in neutral aqueous solution by reversed‐phase liquid chromatography

The temperature‐induced conformational transition of bovine serum albumin (BSA) in neutral aqueous solution was studied using intrinsic fluorescence emission spectrum, reversed‐phase liquid chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and the conformation transition thermodynamic parameters were determined in the temperature range 12–50 °C. The results showed that, in the temperature range 12–20 °C, BSA only existed in a single conformation state A, while in the temperature range 22–50 °C, it existed in two different conformation states: A and B. The percentage of conformation state A decreased while that of conformation state B increased with the increase in temperatures, and when temperature approached 50 °C conformation state B accounted for approximately 25% of all conformation states of BSA. In the conformational transition of BSA from conformation state A to conformation state B, the positive enthalpy change, entropy change and free energy changes demonstrated that the conformational transition was endothermic, nonspontaneous and mainly entropy‐driven. © 2013 The Authors. Biomedical Chromatography published by John Wiley & Sons, Ltd.     

Thermal analysis of the polymerization process on the surface of inorganic fillers

The thermal polymerization of pentabromobenzyl (mono)acrylate (PBB-MA) on the surface of the inorganic fillers Mg(OH)₂ and CaCO₃ was studied. FTIR spectroscopy and extraction of the polymer in bromobenzene show that polypentabromobenzyl acrylate (PBB-PA) was mostly grafted on the surface of Mg(OH)₂. Thermal analysis (TG, DSC, isothermal DSC (IDSC)) demonstrated an increase in polymerization starting temperature, and differences in polymerization enthalpy and apparent activation energy when an inorganic filler is added. These differences depend on the chemical composition of the filler used.The authors acknowledge valuable discussions with Prof. S. Yariv. The authors are also grateful to Berecha Foundation (Geneva) for the financial support of this work.     

Modelling of the phase transition of nanoscale confined liquid crystal

By dividing the bulk melting entropy, a simple thermodynamic model without any adjustable parameter for the size-dependent melting transition temperature has been extended to interpret the melting and freezing transitions of liquid crystals (LCs) confined in nanopores. The results show that as the size of the nanopore decreases, the melting, clearing and freezing transition temperatures of LCs drop. The transition temperatures directly depend on the density of hydrogen bond at the interface between inner pore wall and LC molecules. The model predictions agree well with the corresponding experimental results of LCs p-azoxyanisole and 4-pentyl-4′-cyanobiphenyl confined in nanopores.     

Thermal analysis study of some transition metal complexes by TG and DSC methods

The thermodynamic and thermal properties of [Cu(L)₂·Cl₂], [Ni(L)₂]·Cl₂, [Co(L)₂·Cl₂]; L=1,2-bis(o-aminophenoxy)ethane (BAFE), complexes have been investigated. The thermal decomposition of the complexes took place in two distinct steps in endothermic reaction up to 700°C. The activation energy E, the entropy change S ^#, enthalpy H change and Gibbs free energy change G ^# were calculated from the results of thermogravimetry analysis (TG) and heat capacity from the results of differential scanning calorimetry (DSC). It was found that the thermal stabilities and activation energies of the complexes follow the order Ni(II)>Cu(II)>Co(II) and E _Co<E _Ni<E _Cu, respectively.This revised version was published online in November 2005 with corrections to the Cover Date.     

The Thermal Decomposition of Magnesium(II) Complexes with Acetic and Halogenacetic Acids

Thermogravimetry (TG), differential thermal analysis (DTA) and other analytical methods have been applied to the investigation of the thermal behaviour and structure of the compounds Mg(Ac)₂ × 2H₂ O(I), Mg(ClAc)₂ ×2H₂ O(II) and Mg(Cl₂ Ac)₂ ×H₂ O(III) (Ac =CH₃ COO⁻ , ClAc =ClCH2COO⁻ , Cl ₂ Ac =Cl₂ CHCOO⁻ ). The solid phased intermediate and resultant products of thermolysis had been identified. The possible scheme of destruction of the complexes is suggested. The halogenacetato magnesium complexes (II–III) are thermally more stable than the acetatomagnesium complex I. The final products of the decomposition of compounds were MgO. Infrared (IR) data suggest to a unidentate coordination of carboxylate ions to magnesium ions in complexes I–III. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal decomposition of transition metal dithiocarbamates

Transition metal dithiocarbamate complexes, [M(S₂CN(C₂H₅)(CH₂CH₂OH)] (M=Co, Ni, Cu, Zn and Cd) have been prepared and characterized by elemental analysis and infrared spectra. Thermal decomposition of all the complexes occurs in two or three stages. The first stage in all the complexes is always fast with 65-70% mass loss. In all cases the end product is metal oxide except in the case of cobalt complex which gives Co metal as an end product. During decomposition of copper complex, first CuS is formed at ~300°C which is converted into CuSO₄ and finally CuO is formed. However, decomposition in helium atmosphere yields CuS. SEM studies of transition metal dithiocarbamates reveal needle shape crystalline phase at room temperature and formation of metal sulphide/oxide at higher temperatures. The activation energy varies in a large range of 33.8-188.3 kJ mol^-1, being minimum for the Cu complex and maximum for the Zn complex possibly due to d ¹⁰ configuration. In the case of Ni, Zn and Cd complexes the order of reaction is two suggesting bimolecular process involving intermolecular rearrangement. However, in other cases it is a unimolecular process. Large negative values of ΔS ^# for all the complexes suggest that the decomposition process involves rearrangement. This revised version was published online in July 2006 with corrections to the Cover Date.     

An investigation on the solid state pyrolytic decomposition of bimetallic oxalate precursors of Ca, Sr and Ba with cobalt: A mechanistic approach

The mixed metal oxalate precursors, calcium(II)bis(oxalato)cobaltate(II)hydrate (COC), strontium(II)bis(oxalato)cobaltate(II)pentahydrate (SOC) and barium(II)bis(oxalato)cobaltate(II)octahydrate (BOC) have been synthesized and their thermal stability was investigated. The complexes were characterized by elemental analysis, IR spectral and X-ray powder diffraction studies. Thermal decomposition studies (TG, DTG and DTA) in air showed that the compound COC decomposed mainly to CaC₂O₄ and Co₃O₄ at 340 °C, and a mixture of CaCO₃ and Co₃O₄ identified at 510 °C. A mixture of CaCO₃ and Ca₃Co₂O₆ along with the oxides and carbides of both the cobalt and calcium were attributed at 1000 °C as end products. DSC study in nitrogen ascertained the formation of a mixture of CaO and CoO along with a trace of carbon at 550 °C. The mixture species, SrC₂O₄, CoC₂O₄ and Co₃O₄ were generated at 255 °C in case of SOC in air, which ultimately changed to CoSrO₃, SrCO₃ and oxides of strontium and cobalt at 1000 °C. The several mixture species also generated as intermediate at 332 and 532 °C. The DSC study in nitrogen indicated the formation of CoSrO_x (0.5 < x < 1) as end product. In case of BOC in air, a mixture of BaCoO₂, BaO, CoO and carbides are identified as end product at 1000 °C through the generation of several intermediate species at 350 and 530 °C. A mixture of BaO and CoO is identified as end product in DSC study in nitrogen. The kinetic parameters have been evaluated for all the dehydration and decomposition steps of all the three compounds using four non-mechanistic equations. Using seven mechanistic equations, the kind of dominance of kinetic control mechanism of the dehydration and decomposition steps are also inferred. The kinetic parameters, ΔH and ΔS of all the steps are explored from the DSC studies. Some of the decomposition products are identified by IR and X-ray powder diffraction studies.     

Studies on Energetic (Non) Compounds. Part 21: Preparation and thermal decomposition of ring substituted dimethyl anilinium bromides

Six isomeric dimethyl anilinium bromides (DMABr) have been prepared and characterized by elemental and spectroscopic studies. Thermal decomposition of these salts has been studied by TG and simultaneous TG-DTA techniques. Kinetic parameters have been evaluated from isothermal TG data using contracting area and contracting cube equations. The decomposition pathways have also been suggested which involves simultaneous sublimation (at lower temperature) and dissociative vaporization/decomposition (at higher temperature). This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of pozzolanic activity of natural and artificial pozzolans by thermal analysis

In this research, the pozzolanic activity of natural and artificial pozzolan used for preparation of restoration mortars was evaluated. For this purpose, several pastes were prepared, by mixing two artificial pozzolans and a natural one with commercial hydrated lime, in different ratios. The pastes were cured in standard conditions (RH = 98%, T = 25 °C). The pozzolanic activity was evaluated by using simultaneous differential thermal and thermogravimetric analysis (DTA/TG) after curing for 3, 7, 14, 28 days. The obtained results revealed that the various lime/pozzolan pastes displayed different reaction kinetics and therefore the various pozzolans present different reactivity, in proportion to its mineralogical, physical and chemical characteristics.     

Synthesis and thermal decomposition of mixed Gd-Nd oxalates

Several (Gd_1−xNd_x)₂[C₂O₄]₃·nH₂O samples (0≤x≤1) were prepared by a coprecipitation method: the precipitation is quantitative and all the samples are homogeneous in stoichiometry. XRD analyses have shown that a complete solid solution is formed over the whole range of compositions. The dried Gd rich oxalates have initially a low water content which gradually increases with the Nd content. All the oxalates decompose in O₂ around 700°C either into a single mixed oxide or in a mixture of oxides through several steps, which can be ascribed to the loss of water and CO₂.     

Thermocatalytic removal of carbonaceous materials

Decomposition and removal of carbonizate was performed over platinum catalysts supported on two types of alumina differing in the surface area: low surface area one (LSA) and high surface one (HSA). For the sake of comparison, the performance of platinum catalyst supported on silica and bimetallic platinum-rhenium catalysts was analyzed. It has been shown that all platinum catalysts examined caused an increase in the removal of carbonizate. The activity of these catalysts was independent of the kind of support applied or addition of rhenium as a second component. The online version of the original article can be found at