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1.
Naumov P. Jordanovska V. Boyanov B. Jovanovski G. 《Journal of Thermal Analysis and Calorimetry》2001,66(2):469-477
The complexes [M(HIm)4(H2O)2](sac)2 (M=Co, Ni) and [Cd(HIm)2(sac)2]2 with saccharin (sac) and imidazole (HIm) were synthesized and their thermal (TG, DTG and DTA) behaviour in the interval from
room temperature up to 1000°C in a static air atmosphere was investigated. Irrespectively of whether the deprotonated saccharinato
residues are present as ligands or ions or both as ligands and ions, the anhydrous complexes regularly decompose in two stages.
The thermal data of 16 saccharinato complexes (including the title compounds) were correlated with the respective structural
data. The general thermal stability order of the saccharinato complexes can be represented as: Pb(II)<Zn(II)<Co(II)Ni(II)<Cd(II)
(the stability of the Cu saccharinates depends on the particular compound) and is dictated by
several structural factors, e.g. metal ionic radii, participation of the water in the coordination sphere of the metal and
other structural characteristics.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
On evaporation at room temperature of an aqueous reaction mixture of Ln(III) sulfate and ethanolammonium sulfate in a molar ratio higher than 1∶16, crystal products with a waxy feel were obtained. They were identified by means of the X-ray powder diffraction patterns and it was concluded that they are isostructural. The results of elemental analysis and the mass losses by TG analysis indicated the formation of double sulfates with general formula: (HOCH2CH2NH3)4Ln2(SO4)5·4.5H2O (Ln=La, Ce, Pr or Nd) Their thermal decompositions in static atmosphere in the temperature range from ambient up to 1173 K took place in a similar way, and mainly Ln2O2SO4 was obtained as final product. The exception was the Ce compound, which decomposed to CeO2. The double sulfates decomposed in many not well-differentiated steps. From the mass losses occurring during thermal decomposition, the mode of thermal decomposition was presumed. The X-ray powder diffraction patterns of Ln2O2SO4 (Ln=La, Pr and Nd) show that they are also isostructural. 相似文献
3.
On the refluxing ofM(II) oxalate (M=Mn, Co, Ni, Cu, Zn or Cd) and 2-ethanolamine in chloroform, the following complexes were obtained: MnC2O4·HOCH2CH2NH2·H2O, CoC2O4·2HOCH2CH2NH2, Ni2(C2O4)2·5HOCH2CH2NH2·3H2O, Cu2(C2O4)2·5HOCH2CH2NH2, Zn2(C2O4)2·5HOCH2CH2NH2·2H2O and Cd2(C2O4)2·HOCH2CH2NH2·2H2O. Following the reaction ofM(II) oxalate with 2-ethanolamine in the presence of ethanolammonium oxalate, a compound with the empirical formula ZnC2O4·HOCH2CH2NH2·2H2O1 was isolated. The complexes were identified by using elemental analysis, X-ray powder diffraction patterns, IR spectra, and thermogravimetric and differential thermal analysis. The IR spectra and X-ray powder diffraction patterns showed that the complexes obtained were not isostructural. Their thermal decompositions, in the temperature interval between 20 and about 900°C, also take place in different ways, mainly through the formation of different amine complexes. The DTA curves exhibit a number of thermal effects. 相似文献
4.
Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献5.
Jayasree RS Nayar VU Jordanovska V 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(2):278-284
Infrared and Raman spectra of four rare earth (Ho, Eu, Nd and Pr) double sulphates have been recorded and analysed based on the vibrations of methyl ammonium cations, sulphate anions and water molecules. Formation of hydrogen bonds of the type N-H...O and O-H...O are identified in all the compounds. Bifurcated hydrogen bonds are present in the compounds with dimethyl ammonium cations. The sulphate anions are distorted and occupy a lower site symmetry in the compounds. The bands obtained for (CH(3))(2)NH(2) and SO(4)(2-) ions indicate that the structural bonding of (CH(3))(2)NH(2)Eu(SO(4))(2).H(2)O and (CH(3))(2)NH(2)Ho(SO(4))(2).4H(2)O is identical. Electronic transition bands of Eu(3+) and Nd(3+) observed in the Raman spectra of these two compounds have been identified and discussed. 相似文献
6.
Double sulphates of rare earths with dimethylammonium, with empirical formula (CH3)2NH2Ln(SO4)2·4H2O (Ln=Tb, Dy, Ho, Er, Tm, Yb, Lu and Y), were studied by means of thermogravimetry, derivative thermogravimetry and differential thermal analysis from 20 to 700°. Quantitative gravimetric analysis was used for the determination of rare earths and sulphate. The mechanism of thermal decomposition is also suggested.
Zusammenfassung Doppelsulfate der seltenen Erden mit Dimethylammoniumionen der empirischen Formel (CH3)2NH2Ln(SO4)2·4H2O (Ln=Tb, Dy, Ho, Er, Tm, Yb, Lu und Y) wurden mittels TG, DTG und DTA im Temperaturbereich von 20–700° untersucht. Die Seltenen Erden und Sulfat wurden gravimetrisch bestimmt. Ein Mechanismus der thermischen Zersetzung wird vorgeschlagen.
, 20–700° (3)2N2Ln(S4)2·42, Ln=Tb, Dy, , Er, Tm, Yb, Lu Y. . .相似文献
7.
The double sulfates of Tm, Yb and Lu with monomethylammonium were obtained by evaporation of an aqueous mixture of rare earths(III) sulfate and monomethylammonium sulfate at room temperature and treatment of the concentrated mixture with ethanol. After identification of the double sulfates, they were examined by means of TG, DTG and DTA analysis, from 20 to 700°. Two clearly separated stages of thermal decomposition were evident. It was possible to determine the stoichiometry of the obtained compounds from the TG curves.
Zusammenfassung Die Doppelsulfate von Tm,Yb und Lu mit Monomethylammonium wurden durch Verdampfen eines wäßrigen Gemisches aus Seltenerden(III)-sulfaten und Monomethylammoniumsulfate bei Raumtemperatur und durch Behandlung des konzentrierten Gemisches mit Ethanol erhalten. Nach Identifizierung der Doppelsulfate wurden diese im Temperaturbereich 20–700° mittels TG, DTG und DTA- Analyse untersucht. Zwei eindeutig separate thermische Zersetzungsschritte wurden deutlich. Anhand der TG-Kurven war eine Bestimmung der Stöchiometrie der erhaltenen Verbindungen möglich.相似文献
8.
Upon evaporation at room temperature of an aqueous mixture containing Al(III) sulfate and trishydroxymethyl-ammoniummethane
sulfate in a molar ratio 1:2, double sulfate as crystalline product was obtained. The stoichiometry of the obtained compound
was determined by means of elemental and TG analysis. For identification, IR-spectra and X-ray powder diffraction patterns
were done. It was found that the general formula of the obtained compound is Al(HOCH2)3CNH3(SO4)2·6H2O. as revealed by TG, DTG and DTA analysis, the dehydration of the AL-compound takes place in one step which points out that
the six water molecules are bonded in the same way. The thermal decomposition of the anhydrous compound starts at about 260°C
and is very complex. This process takes place in many steps which are not well resolved. The pathway of the thermal decomposition
is also supposed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
When reaction mixtures of rare earth(III) sulphates and tetramethylammonium sulphate in molar ratios of from 1∶4 to 1∶12 were evaporated at ambient temperature and the concentrated reaction mixture was treated with ethanol, double sulphates with general empirical formula (CH3)4NLn(SO4)2·2H2O (Ln=Ho?Lu and Y) were obtained as reaction products. The crystalline products were identified by quantitative analysis, X-ray powder diffraction patterns and TG, DTG and DTA analysis. They were found to be isostructural. Their thermal decomposition took place in three stages. The temperature range of the dehydration mainly decreased from Ho to Lu. The thermal decomposition in the second and third stages occurred with many thermal events. As final product, Ln2O(SO4)2 was obtained. 相似文献
10.
On evaporation at room temperature of an aqueous mixture of Ln(III) sulphate and ethanolammonium sulphate in a molar ratio
higher than 1:12, in the presence of sulphuric acid, double sulphates of Sm, Eu, Ho, Tm, Yb and Y with a waxy feel were obtained.
The stoichiometry of the obtained compounds was determined by means of elemental and TG analysis. On the basis of X-ray powder
diffraction patterns it was concluded that an isostructural group with a general formula: Ln2(HOCH2CH2NH3)8(SO4)7·8H2O was obtained. The above compounds have a stoichiometry and a crystal structure different from those of the double sulphates
of La, Ce, Pr and Nd with the same monovalent cation, as presented earlier.
The thermal decomposition of the investigated compounds in the temperature range from ambient temperature up to 1173 K occurred
in a similar way, mainly in three not well-differentiated steps. Lanthanide oxysulphates were obtained as final products.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献