Thermal characterization of mercury(II) bis(dialkyldithiocarbamate) complexes

Summary Solid-state M-4-MeO-Bz compounds, where M stands for bivalent Mn, Co, Ni, Cu and Zn and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to have information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.     

Thermoanalytical study of heavier trivalent lanthanides fumarates

Solid-state heavier lanthanides fumarates compounds have been synthesized, and the compounds were characterized by employing simultaneous thermogravimetry and differential thermal analysis (TG–DTA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), TG coupled to FTIR, elemental analysis, and complexometry. On heating, the dehydration occurs in a single and two consecutive steps and the thermal decomposition of the anhydrous compounds occurs in consecutive and/or overlapping steps, with formation of the respective oxides: Tb₄O₇ and Ln₂O₃ (Ln=Dy to Lu). The results also led to information about composition, thermal behavior, and the type of coordination of the isolated compounds.     

Thermal study of zinc(II) salicylate complex compounds with bioactive ligands

Five new complex compounds of general formula Zn(Hsal)_2·L₂·nH₂O (where Hsal=OHC₆H₄COO^-, L=thiourea (tu), nicotinamide (nam), caffeine (caf), theobromine (tbr), n=2-4), were prepared and characterized by chemical analysis, IR spectroscopy and studied by methods of thermal analysis (TG/DTG, DTA). It was found that the thermal decomposition of hydrated compounds starts with the release of water molecules. During the thermal decomposition of anhydrous compounds the release of organic ligands take place followed by the decomposition of salicylate anion. Zinc oxide was found as the final product of the thermal decomposition heated up to 800°C. RTG powder diffraction method, IR spectra and chemical analysis were used for the determination of products of the thermal decomposition. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal behavior of Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN) and its complexes

The thermal decomposition in air and in nitrogen atmosphere of binuclear complex compounds of Cu(II) and Co(II) containing the Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2 diaminoethane (TAMEN) as a ligand, Cu₂(TAMEN)Cl₄ and Co₂(TAMEN)Cl₄, were investigated. X-ray powder diffractometry, infrared spectroscopy and simultaneous thermogravimetry-differential thermal analysis (TG-DTA), have been used to characterize and to study the thermal behavior of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and decomposition mechanism of the compounds.     

Solid-state compounds of 2-methoxybenzylidenepyruvate and 2-methoxycinnamyllidenepyruvate with thorium (IV)

Solid-state compounds of general formula ThL₄·nH₂O, where L represents 2-methoxybenzylidenepyruvate and 2-methoxycynamylidenepyruvate, were synthesized. Complexometric titrations with EDTA, thermogravimetry (TG), differential thermal analysis (DTA), X-ray powder diffractometry, elemental analysis (EA), and infrared spectroscopy have been employed to characterize and to study the thermal behavior of these compounds in dynamic air atmosphere. The results led to informations about the composition, dehydration, crystallinity, and thermal decomposition of the isolated compounds. The performed molecular calculations in this study were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FT-IR spectra supplying structural and physicochemical parameters.     

Thermal behavior of Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2 diaminoethane (TAMEN) and its binuclear complexes

The thermal decomposition of Mannich base N,N′-tetra(4-antipyrylmethyl)-1,2-diaminoethane (TAMEN), and its Ni(II), binuclear complex, Ni₂(TAMEN)Cl₄, in air and in nitrogen atmosphere, were investigated. X-ray powder diffractometry, infrared spectroscopy and simultaneous thermogravimetry-differential thermal analysis (TG-DTA), have been used to characterize and to study the thermal behavior of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and decomposition mechanism of the compound.     

Solid-state Compounds of 4-chloro-benzylidenepyruvate With Lanthanides. Preparation and thermal studies

Solid-state compounds Ln-4Cl-BP, where Ln represents lighter trivalent lanthanides and 4Cl-BP is 4-chlorobenzylidenepyruvate, were prepared. Thermogravimetry, derivative thermogravimetry (TG and DTG), differential scanning calorimetry (DSC) and other methods of analysis were used to characterize and to study the thermal behaviour of these compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal study of zinc(II) 4-chlorosalicylate complex compounds with bioactive ligands

Three new complex compounds of general formula Zn{4-ClC₆H₃-2-(OH)COO}₂⋅L₂⋅nH₂O (where L=thiourea (tu), nicotinamide (nam), caffeine (caf), n=2,3), were prepared and characterized by chemical analysis, IR spectroscopy and their thermal properties were studied by TG/DTG, DTA methods. It was found that the thermal decomposition of hydrated compounds starts with the release of water molecules. During the thermal decomposition of anhydrous compounds the release of organic ligands take place followed by the decomposition of salicylate anion. Zinc oxide was found as the final product of the thermal decomposition performed up to 650°C. RTG powder diffraction method, IR spectra and chemical analysis were used for the determination of products of the thermal decomposition.     

Solid-state compounds of 2-methoxybenzylidenepyruvate with some bivalent metal ions

Solid-state M-2-MeO-BP compounds, where M represents bivalent Mn, Fe, Co, Ni, Cu, Zn and 2-MeO-BP is 2-methoxybenzylidenepyruvate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal stability and thermal decomposition of these compounds. The results led to information about the composition, dehydration, crystallinity and thermal decomposition of the isolated compounds.     

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

Solid state Ln–L compounds, where Ln stands for light trivalent lanthanides (L–Gd) and L is tartrate, have been synthesized. Thermogravimetry and differential thermal analysis (TG/DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration and thermal decomposition of the isolated compounds.     

Synthesis,characterization and thermal behaviour of solid-state compounds of yttrium and lanthanide benzoates

Solid-state Ln(Bz)₃·H₂O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy and chemical analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.     

An Unusual Layered Crystal Packing Gives Rise to a Superior Thermal Stability of Energetic Salt of 3,6‐Bishydrazino‐1,2,4,5‐tetrazine

Five energetic salts of 3,6‐bishydrazino‐1,2,4,5‐tetrazine (BHT), namely (BHT)₂(NTO)₃ ( 3 ), (BHT)(BTT) · 2H₂O ( 4 ), (BHT)(DNP)₂ ( 5 ), (BHT)(NATr)₂ ( 6 ), and (BHT)(FOX‐7)₂ ( 7 ), were synthesized and fully characterized by elemental analysis, FT‐IR, and mass spectra. The crystal structures of salts 3 and 4 were obtained and determined. Sensitivities towards outside stimuli and thermal behaviors of all the compounds were investigated, besides, thermodynamics of both 3 and 4 were calculated as well. The compounds 3 – 7 exhibit splendid thermal stabilities and satisfactory sensitivities simultaneously. Notably, unlike the previously known layered packing, compound 4 was found to adopt an unusual layered crystal packing with arch layers alternately arranged upward or downward. It may play an important role in contributing to its superior thermal stability (350 °C), providing an enlightening thinking to design new highly thermal stable energetic materials.     

Synthesis and Thermal Properties of Three Energetic Ion Salts of 3,6-Bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine

Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesized and characterized by elemental analysis, Fourier transform infrared spectrometry, NMR spectroscopy, and ^13C NMR spectroscopy. The crystal structure of compound 1 was determined by single-crystal X-ray crystallography, and structural analysis revealed that it belonged to the monoclinic system with P21/c space group. In addition, the thermal behavior of the three compounds was studied by differential scanning calorimetry and thermogravimetry techniques. The thermal decomposition peak temperatures of the compounds were 574.89, 545.60, and 606.72 K, indicating that the three ion salts exhibited good thermal stability. Tlie kinetic mechanism equations of the main decomposition process and the entropy of activation(△S^≠), enthalpy of activation(△H^≠), and Gibbs free energy of activation(△G^≠) of the three compounds were also obtained. Moreover, the thermal safety of the compounds was evaluated by the values of the self^accelerated decomposition temperature(Tsadt)5 thermal ignition temperature(TTIT), and critical temperature of thermal explosion(7b). The results showed that all the compounds demonstrated good thermal safety, and the thermal safety of compound 3 was better than that of the others.     

Use of thermal analysis techniques for evaluation of the stability and chemical properties of papaya biodiesel (<Emphasis Type="Italic">Carica Papaya</Emphasis> L.) at low temperatures

Solid state Ln₂–L₃ compounds, where Ln stands for light trivalent lanthanides (lanthanum to gadolinium), except promethium, and L is folate (C₁₉H₁₇N₇O₆), have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy (FTIR), TG coupled to FTIR, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, ligand’s denticity, thermal stability, thermal behaviour and identification of the gaseous products evolved during the thermal decomposition of these compounds.     

Synthesis, characterization and thermal behaviour of solid-state tartrates of heavy trivalent lanthanides and yttrium(III)

Solid state Ln₂-L₃ compounds, where Ln stands for heavy trivalent lanthanides (terbium to lutetium) and yttrium, and L is tartrate [(C₄H₄O₆)^?2] have been synthesized. Simultaneous thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray powder diffractometry, infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, ligand??s denticity, thermal stability and thermal behaviour of these compounds.     

Solid-state compounds of 2-chlorobenzylidenepyruvate with some bivalent metal ions

Solid-state M-2-Cl-BP, where M stands for Mn, Fe, Co, Ni, Cu, Zn and Pb and 2-Cl-BP is 2-chlorobenzylidenepyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.     

Spectroscopic study and thermal behavior of trivalent lanthanides and yttrium(III) chelates of EDTA using TG-DSC, FTIR, and TG-DSC coupled to FTIR

Solid-state compounds of yttrium and lanthanide chelates of ethylenediaminetetraacetic acid have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), theoretical and experimental infrared spectroscopy (FTIR), elemental analysis, complexometry and TG-DSC coupled to FTIR were used to characterize and to study the thermal decomposition of these compounds. The results provided information about the composition, dehydration, thermal stability, thermal decomposition and identification of gaseous products evolved during the thermal decomposition of these compounds. The theoretical and experimental spectroscopic data suggest the possible modes of coordination of the ligand with the lanthanum and terbium metal ions.     

Syntheses and Crystal Structures of 9-Ethyl-1,3,6,8-tetra-aryl-9H-carbazole Compounds

The title compounds 9-ethyl-1,3,6,8-tetra-p-tolyl-9H-carbazole (1) and 9-ethyl-1,3,6,8-tetrakis-(4-fluoro-phenyl)-9H-carbazole (2) were synthesized and characterized by single-crystal X-ray diffraction. Thereinto, the crystal structures of compounds 1 and 2 were composed by asymmetry units. The ratio of compounds 1 and 2 to the solvent molecule cyclohexane (CYH) is 4/3. X-ray analysis reveals that the 1,3,6,8-phenyl groups are distorted at large angles relative to the planar carbazole ring. Furthermore, the luminescent and thermal properties of 1 and 2 have also been investigated. It can be seen that thermal stability of compound 1 with p-tolyl is better than that of 2 with 4-fluoro-phenyl. Fluorescence spectra analysis showed that compounds 1 and 2 have strong UV emission.     

Inclusion by a fluorenyl host with volatile guests: structures, thermal stability and kinetics

The structures of the inclusion compounds formed by the host H = 9,9'-(biphenyl-4,4'-diyl)bis(fluoren-9-ol) with N,N-dimethylacetamide (H.2DMA and H.4DMA), 1,4-dioxane (H.3DIOX), methyl ethyl ketone (H.2MEK), as well as that of the apohost have been elucidated. The compounds were characterised by thermal analysis and solid state NMR, and the kinetics of desorption of H.4DMA, H.2DMA and H.3DIOX have been examined.     

Effect of metal compounds on thermal degradation behavior of aliphatic poly(hydroxyalkanoic acid)s

Effect of metal compounds on the thermal degradation behaviors of poly(3-hydroxybutyric acid) (P(3HB)), poly(4-hydroxybutyric acid) (P(4HB)), and poly(?-caprolactone) (PCL) was investigated by means of thermogravimetric and pyrolysis-gas chromatograph mass spectrometric analyses. Na and Ca compounds accelerated a random chain scission of P(3HB) molecules resulting in a decrease of thermal degradation temperature, whereas the contribution of Zn, Sn, Al compounds to the thermal degradation of P(3HB) was very small. In contrast to P(3HB), Zn, Sn and Al compounds induced the thermal degradation of PCL at lower temperature range by catalyzing the selective unzipping depolymerization from ω-hydroxyl chain end. Transesterification reaction of PCL molecules could be facilitated by the presence of Ca compound, while the gravimetric change was detected at almost identical temperature region regardless of the content of Ca compound. According to the lactonizing characteristic of monomer unit, the thermal degradation of P(4HB) progressed by the cyclic rupture via unzipping reaction from the ω-hydroxyl chain end or/and random intramolecular transesterification at the main chain with a release of γ-butyrolactone as volatile product. Each of metal compounds used in this study was effective to catalyze the cyclic rupture of P(4HB) molecules, and the degradation rate was accelerated by the presence of metal compounds.