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1.
Characterization, thermal stability and thermal decomposition of transition metal malonates, MCH 2C 2O 4· nH 2O (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II)), as well as, the thermal behaviour of malonic acid (C 3H 4O 4) and its sodium salt (Na 2CH 2C 2O 4·H 2O) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry. The dehydration, as well as, the thermal decomposition of the anhydrous compounds occurs in a single step. For the sodium malonate the final residue up to 700 °C is sodium carbonate, while the transition metal malonates the final residue up to 335 °C (Mn), 400 °C (Fe), 340 °C (Co), 350 °C (Ni), 520 °C (Cu) and 450 °C (Zn) is Mn 3O 4, Fe 2O 3, Co 3O 4, NiO, CuO and ZnO, respectively. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds. 相似文献
2.
Semiconducting nano-metal oxides (Fe3O4, Co3O4, NiO, CoFe2O4 and NiFe2O4) were synthesized by thermal decomposition of their oxalate precursors. Using DSC technique, effect of nano-metal oxides [5 m m?1 (%)] on the reaction pathway and mechanism of thermal decomposition of Ce2 (C2O4)3·10H2O in flowing atmosphere of N2 was investigated under linear non-isothermal condition. Performing the kinetic deconvolution method, physico-geometrical kinetic behavior of the two overlapping heat absorbing steps of both lower and higher temperature reactions was illustrated. Nano-Fe3O4 promoted the dehydration stages by lowering the Ea value to 35–36 kJ mol?1. Nano-Co3O4, nano-CoFe2O4 and nano-NiFe2O4 promoted the dehydration as well as decomposition stages of cerium oxalate decahydrate by decreasing the Ea value. Nano-NiO has shown retarding effect on both dehydration and decomposition stages. 相似文献
3.
Zinc(II) carboxylates with O‐, S‐ and N‐donor ligands are interesting for their structural features, as well as for their antibacterial and antifungal activities. The one‐dimensional zinc(II) coordination complex catena‐poly[[bis(2,4‐dichlorobenzoato‐κ O)zinc(II)]‐μ‐isonicotinamide‐κ 2N1: O], [Zn(C 7H 3Cl 2O 2) 2(C 6H 6N 2O)] n, has been prepared and characterized by IR spectroscopy, single‐crystal X‐ray analysis and thermal analysis. The tetrahedral ZnO 3N coordination about the Zn II cation is built up by the N atom of the pyridine ring, an O atom of the carbonyl group of the isonicotinamide ligand and two O atoms of two dichlorobenzoate ligands. Isonicotinamide serves as a bridge between tetrahedra, with a Zn...Zn distance of 8.8161 (7) Å. Additionally, π–π interactions between the planar benzene rings contribute to the stabilization of the extended structure. The structure is also stabilized by intermolecular hydrogen bonds between the amino and carboxylate groups of the ligands, forming a two‐dimensional network. During thermal decomposition of the complex, isonicotinamide, dichlorobenzene and carbon dioxide were evolved. The final solid product of the thermal decomposition heated up to 1173 K was metallic zinc. 相似文献
4.
Three novel mixed ligand complexes of Ni(II), Zn(II) and Cd(II) with p-chlorobenzote and N,N-diethylnicotinamide were synthesised and characterized on the basis of elemental analysis, FTIR spectroscopic
analysis, solid state UV-Vis spectrometric and magnetic susceptibility data. The thermal behavior of the complexes was studied
by simultaneous TG-DTA methods in static air atmosphere and the mass spectra data were recorded.
According to microanalytical results, formulas of complexes are C 34H 40N 4O 8ClNi, C 34H 40N 4O 8ClZn and C 34H 44N 4O 10ClCd. The complexes contain two moles of coordination waters, two moles p-chlorobenzoate and two mole N,N-diethylnicotinamide (dena) ligands per formula unit. In these complexes, the p-chlorobenzoate and N,N-diethylnicotinamide behave as monodentate ligand through acidic oxygen and nitrogen of pyridine ring.
The decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data. The final
decomposition products were found to be as metal oxides. 相似文献
5.
The thermal decomposition behavior of oxovanadium(IV)hydroxamate complexes of composition [VO(acac)(C 6H 5C(O)NHO)] (I), [VO(C 6H 5C(O)NHO) 2] (II), [VO(acac)(4-ClC 6H 4C(O)NHO)] (III), [VO(4-ClC 6H 4C(O)NHO) 2] (IV) (where acac = (CH 3COCHCOCH 3
–) synthesized from the reactions of VO(acac) 2 with equi- and bimolar amounts of potassium benzohydroxamate and potassium 4-chlorobenzohydroxamate in THF + MeOH solvent
medium has been studied by TG and DTA techniques. TG curves indicated that complexes I, II, and IV undergo decomposition in
single step to yield VO 2 as the final residue, while complex III decomposes in two steps to yield VO(acac) as the likely intermediate and VO 2 as the ultimate product of decomposition. The formation of VO 2 has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stability
for the complexes has been inferred as IV > I > III > II. 相似文献
6.
Abstract Acetone [ N-(3-hydroxy-2-naphthoyl)] hydrazone (H 2AHNH) has been prepared and its structure confirmed by elemental analysis and 1H NMR spectroscopy. It has been used to produce diverse complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and U(VI)O 2 ions. The complexes obtained have been investigated by thermal analysis, spectral studies ( 1H NMR, IR, UV–visible, ESR), and magnetic measurements. IR spectra suggest that H 2AHNH acts as a bidentate ligand. The electronic spectra of the complexes and their magnetic moments provide information about
geometries. The ESR spectra give evidence for the proposed structure and the bonding for some Cu(II) complexes. Thermal decomposition
of the Ni(II) and Cu(II) complexes afforded metal oxides as final products. Kinetic data were obtained for each stage of thermal
degradation of some of the complexes using the Coats–Redfern method. The formation of complexes in solution was studied pH-metrically
and the order of their stability constants (log K) was found to be U(VI)O 2 > Cu(II) > Zn(II) > Ni(II) > Cd(II) > Co(II). Antimicrobial and eukaryotic DNA studies were carried out. 相似文献
7.
A series of new complexes with mixed ligands of the type [ML(C 3H 3O 2) 2]· nH 2O (( (1)
M=Mn, n=1; (2)
M=Co(II), n=2; (3)
M=Ni(II), n=4; (4)
M=Cu(II), n=1.5; (5)
M=Zn(II), n=0; L=3-amino-1,2,4-triazole and (C 3H 3O 2)=acrylate anion) were synthesized and characterised by chemical analysis and IR data. In all complexes the 3-amino-1,2,4-triazole
acts as bridge while the acrylate acts as bidentate ligand except for complex (5) where it is found as unidentate. The thermal behaviour steps were investigated in nitrogen flow. The thermal transformations
are complex processes according to TG and DTG curves including dehydration, acrylate ion and 3-amino-1,2,4-triazole degradation
respectively. The final products of decomposition are the most stable metal oxides, except for complex (4) that leads to metallic copper. 相似文献
8.
The mass spectra of 1,1-dimethyl-1-silacyclobutane (I—as reported by Cherniak et al.), 6, 1,1-dimethyl-1-germacyclobutane (II), 1,1,2,2-tetramethyl-1,2-disilacyclopentane (III) and 1,1,2,2-tetramethyl-1,2-digermacyclopentane (IV) are compared and some correlations between electron-impact fragmentation and thermal decomposition are derived. The mass spectra of the germanium compounds with respect to the silicone compounds are enriched by light fragment ions and exhibit lower intensities of odd-electron ions. The composition of some ions and apparently of neutral fragments coincides with that of the unstable intermediates which are suggested in the thermal decomposition mechanism of some related compounds. The loss of C 2H 4 is more characteristic under electron-impact as well as in thermal decomposition of Si-compounds, while C 3H 6 is preferable eliminated by the Ge-compounds. 相似文献
9.
This paper reports the investigation of the thermal stability of a series of new complexes with mixed ligands of the type
[M(en)(C 3H 3O 2) 2]· nH 2O ((1) M=Ni, n=2; (2) M=Cu, n=0; (3) M=Zn, n=2; en=ethylenediamine and (C 3H 3O 2)=acrylate anion). The thermal behaviour steps were investigated in a nitrogen flow. The thermal transformations are complex
processes according to TG and DTA curves including dehydration, ethylenediamine elimination as well as acrylate thermolysis.
The final products of decomposition are the most stable metal oxides except for complex (2) that generates metallic copper. 相似文献
10.
稀土元素由于特殊的外层电子构型,在与不同类型配体配位时,呈现出丰富多彩的配位行为和结构,其配合物,特别是有机配合物,由于具有发光性强、选择性好的特点,在发光、激光材料创制、结构探针、荧光免疫分析及生物传感器等领域的研究和应用引起广泛关注.氨基酸、肽是各种生物大分子的基本组成单元,咪唑存在于组氨酸、羧肽酶、血红蛋白等生物分子中参与配位或"变构效应"成为活性部位结构,唑环有丰富的能级,其作为含N富电子体系可与稀土离子形成既有生物活性,又有优良光学性能的配合物. 相似文献
11.
The homopolynuclear coordination compound [CoL · 2.5H 2O] n with L=C 2O 4
2− was synthesized by a new unconventional method. It consist in the redox reaction between 1,2-ethanediol and cobalt nitrate
in presence of nitric acid. The coordination compound was characterized by chemical analysis, electronic and vibrational spectra
respectively, thermal analysis. In the coordination compound the Co(II) ion exists in a high spin octahedral configuration
and oxalate anion acts as double-bridge ligand, tetradentate, similar as in CoC 2O 4 · 2H 2O obtained by the classical method. Nonstoichiometric oxide, Co 3O 4+0.25 with deficit in cobalt and normal spinel Co 3O 4 where identified as thermal decomposition intermediates. As final product of decomposition, the oxide CoO was obtained. 相似文献
12.
This paper reports the investigation on the thermal stability of new complexes with mixed ligands of the type [Cd(NN)(C 3H 3O 2) 2(H 2O) m]·nH 2O [( 1) NN: 1,10-phenantroline, m = 1, n = 0; ( 2) NN: 2,2′-bipyridine, m = 0, n = 1.5 and (C 3H 3O 2): acrylate anion]. The IR data indicate a bidentate coordination mode for both heterocyclic amine and acrylate. The in vitro
qualitative and quantitative antimicrobial activity assays showed that the complexes exhibited variable antimicrobial activity
against planktonic as well as biofilm embedded Gram-negative ( Escherichia coli, Klebsiella sp., Proteus sp., Salmonella sp., Shigella sp., Acinetobacter boumani, Pseudomonas aeruginosa), Gram-positive ( Bacillus subtilis, Staphylococcus aureus) and fungal ( Candida albicans) strains, reference and isolated ones from the hospital environment. The thermal behaviour steps were investigated
in synthetic air flow. The thermal transformations are complex processes according to TG and DTA curves including dehydration,
amine as well as acrylate thermolysis. The final products of decomposition are the most stable metal oxides. 相似文献
13.
New zinc(II) salicylate complex compounds of general formula (X-C 6H 3-2-(OH)COO) 2Zn · L n · xH 2O (where X = H, 5-Cl; L = theophylline, urea; n = 2, 4; x = 1, 2, 4) were prepared and their thermal, spectral and biological properties were studied. It was found that the thermal
decomposition of hydrated compounds starts with the release of water. During the thermal decomposition of anhydrous compounds,
the release of salicylic acid, theophylline, urea, CO 2, H 2O and C 6H 5Cl takes place. Zinc oxide was found as the final product of the thermal decomposition heated up to 900 °C. The complexes
were tested against bacteria, yeasts and filamentous fungi. The highest biological activity show 5-chlorosalicylate compounds. 相似文献
14.
New complexes of 2-benzoyl-pyridil-isonicotinoylhydrazone (L) with Cu(II), Co(II), Ni(II) and Mn(II), having formula of type
[ML 2] SO 4· xH 2O (M = Cu 2+, Co 2+, Ni 2+, x = 2 and M = Mn 2+, x = 3), have been synthesised and characterised. All complexes were characterised on the basis of elemental analyses, IR spectroscopy,
UV–VIS–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The thermal behaviour
of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry
(DSC). The structure of L hydrazone was established by X-ray study on single crystal. The ligand works as tridentate NNO,
being coordinated through the azomethine nitrogen, the pyridine nitrogen and carbonylic oxygen. Heats of decomposition, Δ H, associated with the exothermal effects were also determined. 相似文献
15.
MXenes are novel graphene-like 2-D materials. Cu 2O is an effective additive for thermal decomposition of ammonium perchlorate (AP). We reported the synthesis of MXene (Ti 3C 2), Cu 2O and MXene-Cu 2O respectively. The samples were characterized by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Results indicate that the MXene is composed of lots of nano-sheets and the thickness is 30 ± 10 nm, and Cu 2O nanoparticles nucleate and grow heterogeneously directly on the surface of MXene. The effect of these MXene, Cu 2O and MXene-Cu 2O samples on the thermal decomposition of AP were investigated using TG-DSC. The results revealed that MXene-Cu 2O have a great influence on the thermal decomposition of AP than that of pure MXene and Cu 2O. 相似文献
16.
Thermal behavior of various synthesized transition metal surfactant complexes of the type [M(CH 3COO) 4] 2−[C 12H 25NH 3
+] 2 where M: Cu(II), Ni(II), Co(II) has been investigated using Thermogravimetric Analysis (TGA). It was found that pyrolytic
decomposition occurs with melting in metal complexes, and that metal oxides remain as final products. The activation energy
order obtained, E
Cu > E
Ni > E
Co, could be explained on the basis of size of transition metal ion and metal ligand bond strength. In the course of our investigation
on the decomposition of complexes, we carried out a comparative study of different measurement and calculation procedures
for the thermal decomposition. A critical examination was made of the kinetic parameters of non-isothermal thermoanalytic
rate measurement by means of several methods such as Coats–Redfern (CR), Horowitz–Metzger (HM), van Krevelen (vK), Madhusudanan–Krishnan–Ninan
(MKN), and Wanjun–Yuwen–Hen–Cunxin (WYHC). The most appropriate method among these was determined for each decomposition step
according to the least-squares linear regression. It was found that the results obtained using CR method differ considerably
from HM method, as the former method involves a lot of approximations and is not much reliable. The application of thermoanalytic
techniques to the investigation of rate processes has also been discussed. 相似文献
17.
The thermal decomposition of lutetium(III) propionate monohydrate (Lu(C 2H 5CO 2) 3·H 2O) in argon was studied by means of thermogravimetry, differential thermal analysis, IR-spectroscopy and X-ray diffraction. Dehydration takes place around 90 °C. It is followed by the decomposition of the anhydrous propionate to Lu 2O 2CO 3 with evolution of CO 2 and 3-pentanone (C 2H 5COC 2H 5) between 300 °C and 400 °C. The further decomposition of Lu 2O 2CO 3 to Lu 2O 3 is characterized by an intermediate constant mass plateau corresponding to a Lu 2O 2.5(CO 3) 0.5 overall composition and extending from approximately 550 °C to 720 °C. Full conversion to Lu 2O 3 is achieved at about 1000 °C. Whereas the temperatures and solid reaction products of the first two decomposition steps are similar to those previously reported for the thermal decomposition of lanthanum(III) propionate monohydrate, the final decomposition of the oxycarbonate to the rare-earth oxide proceeds in a different way, which is here reminiscent of the thermal decomposition path of Lu(C 3H 5O 2)·2CO(NH 2) 2·2H 2O. 相似文献
18.
Four novel azo compounds were synthesized: o-phenylazo-(C 14H 13N 3O 2) (I), p-bromo-o-phenylazo-(C 14H 13BrN 3O 2) (II), p-methoxy-o-phenylazo-(C 15H 16N 3O 3) (III), and p-nitro-o-phenylazo-p-acetamidophenol (C 14H 13N 4O 4) (IV). These compounds were carefully investigated using elemental analyses, IR, and thermal analyses (TA) in comparison
with electron ionization (EI) mass spectral (MS) fragmentation at 70 eV. Semi-empirical MO calculation, PM3 procedure, has
been carried out on the four azo dyes (I–IV), both as neutral molecules and the corresponding positively charged molecular
ions. These included molecular geometries (bond length, bond order, and charge distribution, heats of formation, and ionization
energies). The mass spectral fragmentation pathways and thermal decomposition mechanisms were reported and interpreted on
the basis of molecular orbital (MO) calculations. They are found to be highly correlated to each other. Also, the Hammett’s
effects of p-methoxy, p-bromo, and p-nitro-substituents of phenyl azo groups on the thermal stability of these dyes (I–IV)
are studied by experimental (TA and MS) in comparison with MO calculations, and the data obtained are discussed. This research
aimed chiefly to throw more light on the structures of the four prepared azo derivatives of acetoamidophenol (p-cetamol).
The data refering to the thermal stability of these dyes can be used in industry for effective dyeing purposes under different
thermal conditions. 相似文献
19.
Abstract Acetone [ N-(3-hydroxy-2-naphthoyl)] hydrazone (H 2AHNH) has been prepared and its structure confirmed by elemental analysis and 1H NMR spectroscopy. It has been used to produce diverse complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and U(VI)O 2 ions. The complexes obtained have been investigated by thermal analysis, spectral studies ( 1H NMR, IR, UV–visible, ESR), and magnetic measurements. IR spectra suggest that H 2AHNH acts as a bidentate ligand. The electronic spectra of the complexes and their magnetic moments provide information about
geometries. The ESR spectra give evidence for the proposed structure and the bonding for some Cu(II) complexes. Thermal decomposition
of the Ni(II) and Cu(II) complexes afforded metal oxides as final products. Kinetic data were obtained for each stage of thermal
degradation of some of the complexes using the Coats–Redfern method. The formation of complexes in solution was studied pH-metrically
and the order of their stability constants (log K) was found to be U(VI)O 2 > Cu(II) > Zn(II) > Ni(II) > Cd(II) > Co(II). Antimicrobial and eukaryotic DNA studies were carried out.
Graphical abstract
相似文献
20.
The mixed 2,4'-bipyridine-oxalato complexes of the formulae M(2,4'-bipy) 2 C 2 O 4 2H 2 O ( M (II)=Mn, Co, Ni, Cu; 2,4'-bipyridine=2,4'-bipy or L ; C 2 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 ML 2 (ox)2H 2 O was discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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