Spectroscopic investigation and thermal behavior of new carbonyl complexes [M(CO)(4)(N-N)(CuX)], (M = W, Mo; N-N=2,2 '-bipyridine, 1,10-phenanthroline; X = Cl, SCN)

M(CO)(4)(N-N)] reacts with CuCl to give new heterobimetallic metal carbonyls of the type [M(CO)(4)(N-N)(CuCl)], M = W, Mo; N-N = 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen). Reactions of [M(CO)(4)(N-N)(CuCl)] with NaSCN produced the series of complexes of general formula [M(CO)(4)(N-N)(CuSCN)]. The i.r. spectral of all the bimetallic carbonyls exhibited the general four m ( CO) band patterns of the precursors. The u.v.-vis. spectral data for precursors and products showed bands associated with pi --> pi* (nitrogen ligands), d-->d (intrametal), as well as MLCT d-->pi* (nitrogen ligands) and MLCT d --> pi*(CO) transitions. The [M(CO)(4)(N-N)(CuX)] (X = Cl, SCN) emission spectra showed only one band associated with the MLCT transition. The t.g. curves revealed a stepwise loss of CO groups. The initial decomposition temperatures of the [M(CO)(4)(N-N)(CuX)] series suggest that the bimetallic compounds are indeed thermally less stable than their precursors, and the X- ray data showed the formation of MO3, CuMO4, Cu2O and CuO as final decomposition products, M = W, Mo. The spectroscopic data suggests that the heterobimetallic compounds are polymeric.

Thermal behavior of the Ti(IV), Zr(IV) and Pb(II) complexes with 5-nitro-8-hydroxyquinoline

Ti(IV), Zr(IV) and Pb(II) complexes with 5-nitro-8-hydroxyquinoline (5-NQ) were obtained by precipitation in acetone/ammonium solution medium. The compounds TiO(C9H5N2O3)(2).0.5H(2)O, ZrO(C9H5N2O3)(2)2H(2)O and Pb(C9H5N2O3)(2) were characterized by Elemental Analysis, X-ray Diffratometry and Infrared Absorption Spectrometry and their thermal behavior followed by TG/DTA. This present study intends to show the variations in the thermal behavior of the compounds and in the composition and/or structure of final oxide residues, in different atmospheres and heating rates.

Preparation, characterization and thermal behavior of double selenates of calcium, beryllium and ammonium.

The preparation and thermal decomposition ammonium selenate and calcium and beryllium selenates have been reported previously. However, there are not any information in the literature concerning the thermal decomposition of double selenates of calcium, of beryllium and ammonium. Thermogravimetry (TG), Differential Thermal Analysis (DTA) were used in the studies and characterisation of these compounds.

Preparation and thermal behavior of mixture of basic carbonate and 4-dimethylaminocinnamylidenepyruvate with lanthanides (III) and yttrium (III) in the solid state

Solid Ln-OKCO3-DMCP compounds, where Ln represents lanthanides (III) and yttrium (III) ions and DMCP is the anion 4-dimethyiaminocinnamylidenepyruvate, have been prepared. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction powder patterns and elemental analysis have been used to characterize the compounds. The thermal stability as well as the thermal decomposition of these compounds were studied using an alumina crucible in an air atmosphere.

Synthesis, characterization and thermal behavior of complexes of Cu(II), Zn(II) and Cd(II) with S,S '-methylenebis(cysteine)

Synthesis and characterization, including data on thermal decomposition, are reported for the complexes of S,S'-methylenebis(cysteine) (djenkolic acid) with copper(II), zinc(II) and cadmium(II): CuC(7)H(12)N(2)O(4)S(2) [I]; ZnC(7)H(12)N(2)O(4)S(2) [II] and CdC(7)H(12)N(2)O(4)S(2) [III] X-ray diffraction showed that the compounds are isostructural and belong to a monoclinic system. According to IR spectra, COO, NH(2) groups and bridging sulfur atoms are the main coordination sites.

Thermal behavior of alpha-(Cu-Al-Ag) alloys

Thermal behavior of alpha-(Cu-Al-Ag) alloys, i.e. alloys with composition less than about 8.5 mass% Al, was studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results indicated that the presence of silver introduces new thermal events ascribed to the formation of a silver-rich phase and, after addition higher amounts than 8 mass% Ag to the Cu-8 mass% Al alloy it is possible to observe the formation of the gamma(1) phase (Al4Cu9), which is only observed in alloys containing minimum of 9 mass% Al. These results may be attributed to some Ag characteristics and its interaction with Cu and Al.

Effect of Ag concentration on the thermal behavior of the Cu-10 mass% Al and Cu-11 mass% Al alloys

In this work the effect of Ag concentration on the thermal behavior of the Cu-10 mass% Al and Cu-11 mass% Al alloys with additions of 4, 6, 8 and 10 mass% Ag was studied using differential scanning calorimetry (DSC), in situ X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results showed that for the Cu-10 mass% Al alloy Ag addition induce the beta'(1) phase formation and for the Cu-11 mass% Al alloy these additions increase the amount of martensite formed on quenching and decrease the stability range of this phase on heating.

Study on the thermal behavior of the complexes of the type [PdX2(tdmPz)] (X = Cl-, Br-, I-, SCN-)

Four new mononuclear Pd(II) complexes of the type [PdX2(tdmPz)] {X = Cl- (1); Br- (2); I- (3); SCN- (4); tdmPz = 1-thiocarbamoyl-3,5-dimethylpyrazole} have been synthesized and characterized by elemental analysis, IR spectroscopy, H-1 and C-13{H-1}-NMR experiments. The thermal behavior of the complexes 1-4 has been investigated by means of thermogravimetry (TG) and differential thermal analysis (DTA). From the initial decomposition temperatures, the thermal stability of the complexes can be ordered in the sequence: 3 < 4 a parts per thousand 2 < 1. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.

Thermal behavior of the Cu-22.55 at.%Al alloy with small Ag additions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Ag addition on the thermal behavior of the Cu-11 mass% Al alloy

In this work the influence of Ag additions on the thermal behavior of the Cu-11 mass% Al alloy was studied using differential scanning calorimetry, in situ X-ray diffractometry and scanning electron microscopy. The results indicated that changes in the heating rate shift the peak attributed to alpha phase formation to higher temperatures, evidencing the diffusive character of this reaction. The activation energy value for the alpha phase formation reaction, obtained from a non-isotherm kinetic model, is close to that corresponding to Cu atoms self diffusion, thus confirming that this reaction is dominated by Cu atoms diffusion through the martensite matrix.

Synthesis, characterization and thermal behavior on solid tartrates of light trivalent lanthanides

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal Behavior and Spectroscopic Study of Neutral and Cationic Mononuclear Cyclopalladated Compounds

The reactions of the precursor [Pd(N,C-dmba)(MeCN)2](NO 3) (1) (dmba = N,N-dimethylbenzylamine), with the proligands 3,5-dimethylpyrazole (Hdmpz), 2-quinolinethiol (qnSH) and 1,1′- bis(diphenylphosphine)ferrocene (dppf) afforded the compounds [Pd(N,C-dmba)(Hdmpz)(ONO2)]0.5CH2Cl2 (2), [Pd(N,C-dmba)(qnSH)(ONO2)] 0.5CH2Cl2 (3) and [Pd(N,C-dmba)(dppf)](NO3) (4), respectively. The mononuclear species 2,3 and 4 were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR spectra show bands which are consistent with terminal monodentate nitrate group for 2-3 and ionic nitrate for 4. The 1H and 13C NMR data confirm that coordination of the organic ligands has occurred and the 31P{1H} NMR data for 4 clearly evidences the occurrence in solution of three cyclopalladated species with the dppf acting as a bridging ligand in two cases and as a chelate in one. The thermal behavior of compounds 1-4 suggests that complex 2 is the most stable. The X-ray diffractometry results show the formation of PdO from 1 and 2, Pd2OSO4 from 3, and of a mixture of PdO and Fe 2(PO4)3 from 4, as final decomposition products.

Thermal behavior of lignin and cellulose from waste composting process

The lignin and cellulose were extracted from reference material (leaves and twigs) and food of compost at different times composting: zero (raw), 30, and 120 days. According to thermogravimetric analysis and its derivative and differential scanning calorimetry curves for these samples, were verified during composting process there were considerable changes in its thermal profiles, as well as, characteristics lignin in cellulose samples and cellulose in lignin samples. These features were found by fourier transformed infrared spectroscopy. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Thermal behavior of some antihistamines

Thermogravimetry (TG), differential scanning calorimetry (DSC), polarized light thermal microscopy (PLTM), as well as X-ray powder diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR) were used to study the thermal behavior and the chemical structure of cimetidine, famotidine, ranitidine-HCl, and nizatidine. The TG-DSC curves show that the famotidine and ranitidine-HCl suffer decomposition during melting and they are thermally less stable in comparison with cimetidine and nizatidine, the latter being the most stable of all the drugs studied in this study. The DSC curves of famotidine and ranitidine-HCl show exothermic peaks immediately after the melting, confirming the occurrence of thermal decomposition. The DSC curves also show that the cimetidine and nizatidine have some thermal stability after melting. The thermal events shown in the PLTM images are consistent with the results shown in the TG-DSC and DSC curves. The XRD patterns show that the cimetidine and famotidine are less crystalline compared with ranitidine-HCl and nizatidine. The theoretical FTIR bands are in agreement with those obtained experimentally, and in some cases, no difference is observed between the theoretical and experimental values, even being identical in one of the cases. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Synthesis, characterization and thermal behavior of solid state compounds of heavy trivalent lanthanide succinates

Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides or yttrium(III) (Tb-Lu, Y) and L is succinate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy, TG-DTA coupled to FTIR, elemental analysis, X-ray powder diffractometry and complexometry were used to characterize and study the thermal behavior of these compounds. For the terbium to thulium and yttrium compounds, the dehydration, as well the thermal decomposition of the anhydrous compound occurs in two consecutive steps, while ytterbium and lutetium the dehydration occurs in a single step. The results also led to information about the ligand's denticity, thermal stability and thermal decomposition of these compounds. © 2013 Elsevier B.V.