共查询到20条相似文献,搜索用时 15 毫秒
1.
M. R. Prathapachandra Kurup S. V. Chandra K. Muraleedharan 《Journal of Thermal Analysis and Calorimetry》2000,61(3):909-914
Zinc(II), cadmium(II) and mercury(II) complexes of o-vanillin oxime have been synthesized and characterized by different physicochemical techniques. All the complexes have been
subjected to non-isothermal decomposition studies in nitrogen atmosphere using thermogravimetry. The kinetic parameters for
the decomposition of these complexes were evaluated using different methods and comparatively better results were obtained
by these different methods. It has also been found that the decomposition processes of all these complexes follow first order
kinetics.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
A series of hydrazinated complexes of mixed nickel manganese zinc ferrous fumarates were synthesized from aqueous metal chlorides solution and sodium fumarate–hydrazine hydrate mixture. These complexes were characterized by chemical analysis, infrared spectroscopy, thermogravimetry-differential scanning calorimetry and isothermal mass loss studies. The hydrazine ligand in these complexes shows bidentate bridging nature while, carboxylate ion displays monodentate behaviour. Thermal decomposition studies indicate 3-step decomposition, involving 2-step dehydrazination and 1-step decarboxylation. The thermal decomposition residues were characterized by X-ray diffractometry, transmission electron microscopy and infrared spectroscopy. 相似文献
3.
We demonstrate here the thermochemical hole burning (THB) effect on a series of N-substituted morpholinium 7,7,8,8-tetracyanoquinodimethane charge-transfer (C-T) complexes for ultra-high-density data storage. A correlation between the decomposition temperature of the charge-transfer complex and the threshold voltage of hole burning was observed: the higher the decomposition temperature, the larger the writing threshold value, suggesting the possibility of molecular design for optimizing the hole burning performance. The macroscopic decomposition properties of these charge-transfer complexes were studied by thermal gravimetry combined with mass spectrometry. Theoretical estimation of the temperature rise induced by scanning tunneling microscopy current heating was also conducted, which indicated that the maximum temperature certainly exceeds the decomposition temperatures of these C-T complexes. These observations are consistent with the thermochemical hole burning mechanism. 相似文献
4.
Barakat AS Gaballa AS Mohammed SF Teleb SM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):814-818
The infrared spectra of the oxodiperoxo and triperoxo complexes, (NH4)[VO(O2)2(phen)].2H2O and (NH4)[V(O2)3(phen)].2H2O have been recorded and the observed bands are assigned on the basis of Cs symmetry. Thermogravimetric (TG) and differential thermal analysis (DTA) measurements on these two complexes were also carried out. A detailed mechanism for the mode of thermal decomposition of the two complexes has been given and supported by infrared spectral measurements on the thermal decomposition products. The data obtained agree quite well with the expected structure and indicate that the final thermal decomposition product of these two complexes is V2O5. 相似文献
5.
Pedro E. Aranha Sandra Romera Mirian P. dos Santos Eder T.G. Cavalheiro 《Thermochimica Acta》2007,453(1):9-13
Several Schiff bases coordinated to vanadyl, VO(Schiff base), were synthesized, characterized and studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. The number of steps and, in particular, the starting temperature of decomposition of these complexes depend on the equatorial ligand. The intermediates of the thermal decomposition processes were characterized by their IR spectra. 相似文献
6.
Abdel-Latif SA Hassib HB Issa YM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,67(3-4):950-957
The formation constants of some transition metal ions Cr(III), Mn(II), Fe(III), Ni(II) and Cu(II) binary complexes containing Schiff bases resulting from condensation of salicylaldehyde with aniline (I), 2-aminopyridine (II), 4-aminopyridine (III) and 2-aminopyrimidine (IV) were determined pH-metrically in ethanolic medium (80%, v/v). The formation constants were determined for all binary complexes. The important infrared (IR) spectral bands corresponding to the active groups in the four ligands and the solid complexes under investigation were studied. The solid complexes have been synthesized and studied by thermogravimetric analysis. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats-Redfern equation. It was found that the thermal decomposition of the complexes follow second order kinetics. The thermodynamic parameters of the decomposition are also reported. The electronic absorption spectra of the investigated ligands were carried out to determine the pK(a) values spectrophotometrically. 相似文献
7.
M. R. P. Kurup E. Lukose K. Muraleedharan 《Journal of Thermal Analysis and Calorimetry》2000,59(3):815-825
Iron(III) complexes of o-vanillin oxime have been synthesized and characterized by different physicochemical techniques. The complexes containing
thiocyanate, iodide and sulphate ionshave been subjected to non-isothermal decomposition studies in N2 using TGand DTG techniques. The kinetic parameters for both stages of decomposition of these complexes were evaluated by
weighted least-squares method using the general approach as well as the Coats–Redfern and Horowitz–Metzger equations. The
results indicate that the values of kinetic parameters obtained by these three different approaches agree well.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Beatriz Ambrozini Edward Ralph Dockal Éder Tadeu Gomes Cavalheiro 《Journal of Thermal Analysis and Calorimetry》2014,115(2):979-986
Thermal analytical behavior of eight chromium(III) complexes with N,N′-bis(salicylidene)ethylenediamine (salen) Schiff bases, Cr(salen), has been investigated regarding their thermal stability and thermal decomposition pathways. Thus, the ligands and the respective chromium(III) complexes of salen-type Schiff bases derived from salicylaldehyde and its 5-chloro, 5-bromo, 5-methoxy, 5-nitro, 3,5-dicloro, 3,5-dibromo, and 3,5-diiodosalicylaldehyde were synthesized, characterized, and submitted to TG/DTG, DTA, and TG–FTIR evolved gas analysis. The number of steps and, in particular, the starting temperature of decomposition of these complexes was dependent of the ligand nature. The gaseous products evolved during the thermal decomposition of these compounds were identified by TG–FTIR. 相似文献
9.
The conditions of thermal decomposition of scandium(III) m-nitrobenzoate, m-chlorobenzoate, m-hydroxybenzoate and m-aminobenzoate were studied. On heating, most of these carboxylates decompose in two steps; only scandium(III) 3-aminobenzoate decomposes in one step. The hydrated complexes first lose crystallization water and are then transformed to Sc2O3. The hydration of the complexes is accompanied by an endothermic effect, and the decomposition of the anhydrous complexes by a strong exothermic effect. Scandium(III) 3-nitrobenzoate decomposes explosively. 相似文献
10.
Vic-dioxime ligandsand their metal complexes are used in analytical, bio, pigment and medicinal chemistry. Complexes of nickel(II),
copper(II), and cobalt(II) with benzylamino-p-chlorophenylglyoxime (BpCPG) are synthesised. Thermal behaviour of these complexes was studied in dynamic nitrogen atmosphere by DTA, DTG and TG techniques.
GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end products were identified
by X-ray powder diffraction. Thermoanalytical data of these complexes are presented in this communication. Interpretation
and mathematical analysis of these data and evaluation of order of reaction, the energy and entropy of activation based on
the integral method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation are
also given. The metal complexes undergo decomposition in three stages and metal oxides remained as end products of the complexes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
A. R. Yaul V. V. Dhande S. G. Bhadange A. S. Aswar 《Russian Journal of Inorganic Chemistry》2011,56(4):549-554
New complexes of MoO2(VI), WO2(VI), Th(IV) and UO2(VI) with aroyl hydrazones have been prepared and characterized by various physicochemical methods. Elemental analysis suggested
1 : 1 metal : ligand stoichiometry for MoO2(VI), WO2(VI), and UO2(VI) complexes whereas 1 : 2 for Th(VI) complexes. The physicochemical studies showed that MoO2(VI), Th(IV) and UO2(VI) complexes are octahedral. The electrical conductivity of these complexes lies in the range 1.00 × 10−7−3.37 × 10−11Ω−1 cm−1 at 373 K. The complexes were found to be quite stable and decomposition of the complexes ended with respective metal oxide
as a final product. The thermal dehydration and decomposition of these complexes were studied kinetically using both Coats-Redfern
and Horowitz-Metzger methods. It was found that the thermal decomposition of the complexes follow first order kinetics. The
thermodynamic parameters of the decomposition are also reported. The biological activities of ligands and their metal complexes
were tested against various microorganisms. 相似文献
12.
采用pH法, 在25.0±0.1℃, I=0.1 mol.dm^-^3 (KNO3)条件下, 测定了13-取代苄基-1, 4, 8, 11-四氮杂环十四烷-12,14-二酮的质子化常数及其与Cu(II)配位的平衡常数。讨论了配体与金属离子的配位方式。在25.0±0.1℃, 离子强度为0.1mol.dm^-^3 (KNO3)下, 采用分光光度法, 研究了这些配体铜(II)配合物的酸分解动力学行为。探讨了配合物酸分解机理,得到了速控步的速率常数。发现配位反应平衡常数与配体的质子化常数及配合物酸分解反应速率常数之间存在较好的Hammett型和Bronsted型直线自由能关系。同时探讨了取代基对配合物生成及酸分解的影响情况。 相似文献
13.
Thermogravimetry has been used to investigate the thermal decomposition kinetics of chloro-, bromo- and acetato complexes of 2-phenyl-1,2,3-triazole-4-carboxalideneaniline with copper(II). The decomposition process consists of two stages for all the complexes. Kinetic parameters were evaluated using the Coats-Redfern equation. Furthermore, the results of the kinetic study have been correlated with the catalytic activity of these complexes in the oxidation of hydroquinone with dioxygen. 相似文献
14.
E.M AbdallaA.A Said 《Thermochimica Acta》2003,405(2):269-277
The thermal decomposition of Co(II), Ni(II) and Cu(II) complexes has been studied using thermogravimetry (TG) and differential TG (DTG). The complexes have been characterized by IR spectroscopy. The results reveal that the decomposition of these complexes is accompanied by the formation of metal acetate as an intermediate fragments. On the basis of the applicability of a non-isothermal kinetic equations, it was demonstrated that the stability of the complexes follows the order Co(II)>Cu(II)>Ni(II). These stably correspond to the strength of chelation between the metal ions and the primary and secondary ligands. A possible mechanism of the thermal decomposition of the complexes is suggested. 相似文献
15.
Nicoleta Petrea Răzvan Petre Andrada Pretorian Constantin Toader Vasile Şomoghi Florentina Neaţu Mihaela Florea Ştefan Neaţu 《Comptes Rendus Chimie》2018,21(3-4):339-345
The catalytic methanolysis of the chemical warfare nerve agents soman, sarin, and VX was investigated by using Cu or Zn complexes. Although VX withstood decontamination, the decomposition yield being around 96%, the soman and sarin deposited on different surfaces were almost fully destroyed under ambient conditions. The catalytic tests performed on a wide range of contaminated surfaces confirm the activity of the investigated catalytic systems, these complexes being suitable, from an economical point of view, for use in the formulation of a possible decomposition kit with military or civilian applicability. 相似文献
16.
The kinetics of thermal decomposition of mixed ligand complexes of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) containing triethanolamine and oxalate have been studied using thermogravimetry (TG) and differential scanning calorimetry (DSC). The decomposition reaction in which the complexes lose one molecule of triethanolamine was found to be first order and the activation energy and pre-exponential factors were calculated using established techniques. The values of Ea obtained for these reactions using a modified form of the Horowitz and Metzger equation were 27.75, 20.54, 18.33, 25.32 and 23.25 kcal mole?1, respectively. Infrared spectral data of these complexes and the intermediates gave additional information about the coordinating nature of the ligands in these complexes. 相似文献
17.
《Thermochimica Acta》1987,114(2):329-336
The conditions of thermal decomposition of aluminium(III), cobalt(II), manganese(II) and nickel(II) 8-hydroxyquinoline complexes have been studied by TG-DSC analysis. The thermal decomposition of these complexes has two stages: dehydration and loss of 8-hydroxyquinoline. The final solid product is an oxide. 相似文献
18.
Dursun Ali Köse 《Russian Journal of Inorganic Chemistry》2007,52(9):1384-1390
Mixed-ligand m-hydroxybenzoate complexes of Co(II), Ni(II), Cu(II), and Zn(II) with nicotinamide were synthesized and characterized by elemental
analysis, FT-IR spectrometry, solid state UV-vis spectrometry, and magnetic susceptibility measurements. The thermal behavior
of the complexes was studied by simultaneous TG-DTA methods in static air atmosphere. The infrared spectral characteristics
of the complexes are discussed and the mass spectra data are recorded. The complexes contain two water molecules, two m-hydroxybenzoato (m-hba), and two nicotinamide (na) ligands per formula unit. In these complexes, the m-hydroxybenzoate and nicotinamide behave as a monodentate ligand through acidic oxygen and nitrogen of the pyridine ring.
The decomposition pathways and the stability of the complexes are interpreted in terms of the structural data. The final decomposition
products were found to be the respective metal oxides.
The text was submitted by the author in English. 相似文献
19.
Preparation, X-ray crystallography, and thermal decomposition of some transition metal perchlorate complexes of hexamethylenetetramine 总被引:1,自引:0,他引:1
Singh G Baranwal BP Kapoor IP Kumar D Fröhlich R 《The journal of physical chemistry. A》2007,111(50):12972-12976
The perchlorate complexes of manganese, nickel, and zinc with hexamethylenetetramine (HMTA) of the general formula [M(H2O-HMTA-H2O)2(H2O-ClO4)2(H2O)2] (where M=Mn, Ni, and Zn) have been prepared and characterized by X-ray crystallography. Thermal studies were undertaken using thermogravimetry (TG), differential thermal analysis (DTA), and explosion delay (DE) measurements. The kinetics of thermal decomposition of these complexes was investigated using isothermal TG data by applying isoconversional method. The decomposition pathways of the complexes have also been proposed. These were found to explode when subjected to higher temperatures. 相似文献
20.
M. S. Masoud T. S. Kassem M. A. Shaker A. E. Ali 《Journal of Thermal Analysis and Calorimetry》2006,84(3):549-555
Iron, cobalt, nickel,
copper, zinc, cadmium and mercury murexide complexes have been prepared and
characterized. The thermal properties of these complexes are studied deeply
by DTA technique where their thermal peaks are explained. The multi-stages
thermal decomposition mechanism is proposed. The thermodynamic parameters
of the decomposition steps are calculated. The entropy change values for all
complexes are of the same magnitude and all transition states of the thermal
reactions are more ordered than the reactants. The thermal reactions proceed
in complicated mechanisms. The fractions appeared in the calculated orders
of the thermal reactions confirmed that these reactions proceeded via complex
mechanisms. 相似文献