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1.
The thermal decomposition behaviour of the complexes of rare earth metals with histidine: RE(His)(NO3)3H2O (RE=La—Nd, Sm—Lu and Y; His=histidine) was investigated by means of TG-DTG techniques. The results indicated that the thermal decomposition processes of the complexes can be divided into three steps. The first step is the loss of crystal water molecules or part of the histidine molecules from the complexes. The second step is the formation of alkaline salts or mixtures of nitrates with alkaline salts after the histidine has been completely lost from the complexes. The third step is the formation of oxides or mixtures of oxides with alkaline salts. The results relating to the three steps indicate that the stabilities of the complexes increase from La to Lu.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
2.
Summary The paper chromatographic resolution potentiality of the solvent system chloroform-acetone-iso-amyl alcohol-11N HCl (1 1 1 0.5v/v) for the metal cations has been tested. Successful results with various multiconstituent mixtures are presented andR
f
values of the common metal ions are tabulated.
Zusammenfassung Das papierchromatographische Trennungsvermögen des Lösungsmittel Systems Chloroform—Aceton—i-Amylalkohol—11-n Salzsäure (1 1 1 0,5v/v) für Metallkationen wurde geprüft. Mit verschiedenen, aus einer Mehrzahl Komponenten bestehenden Gemischen wurden gute Ergebnisse erhalten. DieR f -Werte der üblichen Kationen wurden angegeben.相似文献
3.
Zusammenfassung In Methoxyverbindungen des Bors tritt eine Verminderung der Frequenz der B—O-Valenzschwingung gengenüber den entsprechenden Trideuteromethoxyverbindungen auf. Dies wird durch zufällige Entartung von B—O und CH3 erklärt, die zu einer Abstoßung und zur Vermischung des Schwingungscharakters dieser beiden Schwingungen führt. Hiedurch werden die B—O-Valenzschwingungen zu tieferen und die CH3-Deformationsschwingungen zu höheren Wellenzahlen verschoben. Ähnliche Erscheinungen sind auch in Methoxyborazinen durch Wechselwirkung von BN und CH3 zu beobachten. Diese Deutung gibt auch Hinweise für Zuordnungen in den Spektren von N-Methylborazinderivaten.
Mit 7 Abbildungen 相似文献
In methoxy substituted boron compounds bands arising from B—O stretching and (O)–CH3 deformation modes show accidental degeneracy. The frequency of the CH3 absorption is increased whereas BO is decreased compared to the corresponding CD3-compounds. The spectra of B-methoxyborazines show similar effects between BN and (O)–CH3 bands, which is analogous to interference between BN and (N)–CH3 in N-methylborazines.
Mit 7 Abbildungen 相似文献
4.
Two different models were assumed for BF3-benzaldehyde: a charge transfer complex and a — one. The CNDO/2 and the Mulliken's population analysis were used. From the given numerical results we clearly conclude a — model. An electronic migration from benzaldehyde to BF3 and other results of the population analysis are also discussed. 相似文献
5.
Ming-Sheng Wang Wen-Tong Chen Li-Zhen Cai Guo-Wei Zhou Guo-Cong Guo Jin-Shun Huang 《Journal of Cluster Science》2003,14(4):495-504
The reactions of TMA4Ge4S10 (TMA=tetramethylammonium), Cu(NO3)23H2Oand 4,4-bipy under hydrothermal environment result in the formation of (H2bipy)2Ge4S10(bipy)7H2O (1), which has been structurally characterized by single crystal X-ray analysis. The 3-D structure of 1 can be viewed as an inorganic-organic hybrid supramolecular hydrogen-bonding (hydrogen bonds: O–HO, N–HN, C–HO, N–HO, and O–HS) and - stacking network containing Ge4S4–
10 clusters and novel [H2bipybipyH2bipy] trimers. 相似文献
6.
The frequency shift, , of the O—H stretching mode in the IR spectra of the H-complexes of phenol with electron donor molecules BXi (B is the n- or -donor center and Xi are substituents; a total of eight series), the change in the Gibbs free energy, G, due to H-complexation, and the parameter (a measure of the ability of BXi molecules to donate an electron pair; two series) are determined by both the electrostatic interaction and charge transfer in the formation of H-complex. The , G, and values depend not only on the inductive and resonance effects, but also the polarizability of substituents characterized by the parameters. 相似文献
7.
Zusammenfassung Die 2g1-Kinke wird als Baufehler mit 4 möglichen Lagen im idealisierten PÄ-Kristall elastizitätstheoretisch durch je einen Kräftedipol beschrieben. Die Berechnung des Relaxationsbetrags für den -Prozeß in PÄ — Kinkschritt (II) und Kinksprung (II) — ergibt mit h·c=0,0006 Übereinstimmung mit der in (7) verwendeten paraelastischen Abgleitvorstellung und mit dem Experiment. Mittlere 2g1-Kinkblockgrößeh und Defektanteil der thermischen Ausdehnung werden unter der Nebenbedingung konstanter 2g1-Kinkkonzentrationc diskutiert.
Mit 2 Abbildungen in 3 Einzeldarstellungen und 5 Tabellen
Herrn Dr.H. Oberst zum 65. Geburtstag gewidmet. 相似文献
Summary The 2g1-Kink is considered as an elastic dipole in the idealized PE-crystal, with 4 possible positions, that is 4 dipol-tensors. The calculated relaxation strength for the -process in PE — kinkstep (II) and kinkjump (II) — agrees with the results obtained by considering a simple shear displacement (7) and with experiment, assuming h. The mean number h of 2g1-kinks in a bloc and the thermal expansion due to these kink defects are discussed under the additional condition that 2g1-kinkconcentrationc is constant.
Mit 2 Abbildungen in 3 Einzeldarstellungen und 5 Tabellen
Herrn Dr.H. Oberst zum 65. Geburtstag gewidmet. 相似文献
8.
The — complexes of metal tetraphenylporphinates with benzene, toluene, and xylenes were characterized by means of thermogravimetry. The ability of metalloporphyrins to form — complexes with certain -donor molecules depends largely on the -acceptor capacity of the macroheterocycle, and on the peculiarities of the metal—porphyrin coordinative linkage. Stoichiometry, energy parameters, and thermal stability of the - complexes of metalloporphyrins with various aromatic ligands are determined to a great extent by the molecular structure of solvents.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp.850–853, May, 1993. 相似文献
9.
In the binary Fe–Te system six intermediate solid phases exist with varying ranges of homogeneity. With the exception of the high temperature -phase the magnetic behavior of these phases and in some cases the variation of magnetic properties with composition were investigated by susceptibility measurements in the temperature range from 100 to 300 K. Both the -phase (FeTe1–x
) and the -phase (Fe5Te6) follow theCurie—Weiss law and can be designated as antiferromagnetic compounds according to the negativeWeiss constants of –192 K and –314 K, resp. The magnetic moments identify these two phases as high-spin compounds of Fe. The observed increase of the magnetic moments towards the Ferich limit of the -phase is due to the occupation of the octahedral interstices in the anion sublattice by excess iron and it was explained by a simple model. The magnetic moment of the hypothetical equiatomic compounds FeTe, obtained by extrapolation (3.87 B), as well as the moment of the -phase (3.83 B) are nearly identical and can be interpreted as being due to the existence of three unpaired 3d-electrons per formula unit. For the Te-rich (Fe1–x
Te)-, (Fe1–x
Te)- and (FeTe2)-phases the transition metal is supposed to be in the low-spin state. The observedPauli paramagnetism is not temperature independent but decreases with decreasing temperature. Below 100 K FeTe2 appears to be diamagnetic.
Mit 7 Abbildungen 相似文献
Mit 7 Abbildungen 相似文献
10.
Frederick P. Schwarz 《Journal of solution chemistry》1996,25(5):471-484
A differential scanning calorimeter (DSC) was modified for the determination of enthalpies of solution. The measurements were performed on aqueous solutions of the deoxy- and fluoro-deoxy derivatives of D-glucopyranose (Glu) where the OH group on the C1, C2, C3, and C6 is replaced by H (1HGlu, 2HGlu, 3HGlu, and 6HGlu) and by F (1FGlu, 2FGlu, 3FGlu, and 6FGlu), 4-deoxy 4-fluoro--D-glucopyranoside (4FGlu), 1-methoxy--D-glucopyranoside (MeOGlu), 1-phenoxy--D-glucopyranoside (PheOGlu), D-mannopyranose (Man), and 3-methoxy--D-glucopyranoside (3MeOGlu), at 15.1, 25.0, 35.0, and 45.1°C. The enthalpies of solution sH0(T) ranged from 1.00±0.25 kJ-mol–1 for 6HGlu at 15.1°C to 20.4±1.4 for PhOGlu at 45.1°C and were in good agreement with literature values for Man, Glu, MeOGlu, and 3MeOGlu at 25.0 and 35.0°C and for MeOMan and 2HGlu at 35.0°C. sH0(T) for the derivatives were then extrapolated up to the melting temperature Tm and compared with their enthalpies of fusion, fH also determined from DSC measurements. If the agreement between sH0(Tm) and fH was within the 95% confidence level, then it was concluded that intermolecular interactions between the carbohydrate molecules in the liquid phase were the same as between the carbohydrate and water molecules in the solution phase. This agreement was observed for aqueous solutions of Man, Glu, MeOGlu, 3HGlu, 3FGlu, and 6FGlu. 相似文献
11.
The Piloyan activation energiesE, as well as the initial exotherm temperaturesT
D, are determined for sixN-monoalkyl- and fiveN,N-dialkyl-2,4,6-trinitroanilines. By comparison withR
f-factors, orR
M-functions of paper chromatography, the molecular-structural dependences ofE andT
D are studied for these compounds. Relationships are also found between the termE · T
D
–1
and theR
M-functions. The effects are discussed of the introduction of the 6-nitro group into the TV-substituted 2,4-dinitroanilines, and of the introduction of the 4-nitro group into the 2,6-dinitro analogues, upon the thermal stabilities of the resulting 2,4,6-trinitroanilines.
The authors would like to thank Mrs. Anna Colláková for careful DTA measurements, and Dr. Ladislav Smolka for help in the treatment of the measured results with the Wang 600 computer. 相似文献
Zusammenfassung Die AktivierungsenergienE nach Piloyan und die Anfangswerte der ExothermenT D der sechsN-monoalkyl- und fünfN,N-Dialkyl-2,4,6-trinitroaniline wurden bestimmt. Unter Berücksichtigung des Vergleichs mitR f-Faktoren oderR M-Funktionen der Papierchromatographie wurden die molekularstrukturellen AbhÄngigkeiten der WerteE undT D dieser Verbindungen untersucht. ZusammenhÄnge wurden auch zwischen dem AusdruckE · Tw D –1 und denR M-Funktionen gefunden. Der Einfluss der Einführung der 6-Nitrogruppe in dieN-substituierten 2,4-Dinitroaniline, sowie der Einfluss der Einführung der 4-Nitrogruppe in 2,6-Nitroanaloge auf die ThermostabilitÄt der resultierenden 2,4,6-Trinitroaniline werden erörtert.
Résumé On a déterminé les énergies d'activation par la méthode de Piloyan ainsi que les températures initialesT D de l'effet exothermique de sixN-monoalcoyl- et cinqN,N-dialcoyl-2,4,6-trinitroanilines. En se référant aux facteursR F ou aux valeurs des fonctionsR M en Chromatographie sur papier, on a étudié la dépendance entre les valeurs deE et deT D sur les caractéristiques moléculaires-structurales de ces composés.On a également trouvé des rapports entre le termeE · T D –1 et les fonctionsR M. On discute l'influence de l'introduction du groupe 6-nitro dans les 2,4-dinitroanilinesN-substituées ainsi que l'influence de l'introduction du groupe 4-nitro dans les 2,6-dinitro analogues sur la stabilité thermique des 2,4,6-trinitroanilines qui en résultent.
N-- N,N--2,4,6- E , T D. R f,- R M — , - E T D. E.T D –1 R M-. 6N- 2,4- 4 2,6- 2,4,6- .
The authors would like to thank Mrs. Anna Colláková for careful DTA measurements, and Dr. Ladislav Smolka for help in the treatment of the measured results with the Wang 600 computer. 相似文献
12.
Marek Majdan 《Monatshefte für Chemie / Chemical Monthly》1988,119(10):1079-1089
The correlations between the values of the lgK (K = stability constant of the lanthanide complex) and the reciprocal of the ionic radius 1/r or the sum of the ionization potentials
1
3
I for the lanthanide ions were reviewed for different ligands. A straight-line relationship (lgK – lgK)/lgK vs. (1/r – 1/r)/(1/r) or vs. (
1
3
I –
1
3
I)/
1
3
I was found within the tetrads La-Nd, Gd-Ho, and Er-Lu.
Bemerkungen zum periodischen Wechsel der Stabilitätskonstanten von Lanthaniden-Komplexen
Zusammenfassung Es wurde eine Übersicht der Korrelationen zwischen den Werten von logK (K = Stabilitätskonstante der Lanthanidenkomplexe) und den reziproken Ionenradien 1/r oder der Summe der Ionisierungspotentiale 1 3 I für die Lanthanidenionen für verschiedene Liganden gegeben. Dabei wurde eine lineare Korrelation für (lgK – lgK)/lgK gegen (1/r – 1/r)/(1/r) oder gegen ( 1 3 I – 1 3 I)/1/3 I innerhalb der Tetraden La-Nd, Gd-Ho und Er-Lu aufgefunden.相似文献
13.
F. Grønvold 《Journal of Thermal Analysis and Calorimetry》1978,13(3):419-428
The heat capacity of high-purity indium has been determined by adiabatic-shield calorimetry in the range 300 to 1000 K. Values of thermodynamic functions have been calculated andC
p (1000 K), [H° (1000 K)–H° (298.15 K)], and [S° (1000 K)–S° (298.15 K)] are (27.11±0.15) J K–1 mole–1, (22873±70) J mole–1, and (41.567 ±0.125) J K–1 mole–1, respectively. The enthalpy of fusion is (3283±7) J mole–1 and the melting temperature (429.77±0.01) K. The premelting heat capacity is compatible with the presence of a mole fractionx 1·10–6 of a liquid-soluble/solidinsoluble impurity in the sample.
The assistance of Bjørn Lyng Nielsen with the experimental work is recognized with thanks. 相似文献
Zusammenfassung Die Wärmekapazität von hochreinem Indium wurde im Bereich von 300 bis 1000 K durch adiabatische Schildkalorimetrie bestimmt. Die Berechnungen der thermodynamischen Funktionen:C p (1000 K), [H° (1000 K)–H° (298.15 K)] und [S° (1000 K–S° (298.15 K)] ergab 27.11±0.15 J K–1 Mol–1, (22 875±70) J Mol–1, bzw. (41.567±0.125) J K–1 Mol–1. Die Schmelzenthalpie beträgt (3283±7) J Mol–1 und die Schmelztemperatur (429.77±0.01) K. Die Vorschmelz-Wärmekapazität ist mit der Gegenwart einer Molfraktionx1×10–6 einer flüssig-löslich/fest-unlöslichen Verunreinigung in der Probe vereinbar.
Résumé La chaleur spécifique de l'indium de haute pureté a été déterminée entre 300 et 1000 K par calorimétrie adiabatique. Les valeurs des fonctions thermodynamiques suivantes ont été calculées:C p (1000 K)=(27.11±0.15) J K–1mol–1, [H° (1000 K)–H° (298.15 K)]= (22 875±70) J mol–1 et [S° (1000 K)–S° (298.15 K)]=(41.567±0.125) J K–1 mol–1. L'enthalpie de fusion est (3283±7) J mol–1 et la température de fusion (429.77±0.01) K. La chaleur spécifique de pré-fusion est compatible avec la présence d'une fraction molairex1×10–6 d'une impureté dans l'échantillon, soluble dans le liquide, insoluble dans le solide.
C - 300 1000 . : p(1000 ), [ (1000 ) — H (298,15 )] [S (1000 ) — S (298.15 )], : 27.11±0.15 . –1. –1, 2 2875±70 . –1 41.567±0.125 . – 1–1. 3283±7 .–1, – 429.77±0,01 . - / 1.10–6.
The assistance of Bjørn Lyng Nielsen with the experimental work is recognized with thanks. 相似文献
14.
I. V. Kozhevnikov I. B. Vasilieva V. V. Zarutskii 《Reaction Kinetics and Catalysis Letters》1992,47(1):83-86
Acetonation of L-sorbose—a step of ascorbic acid synthesis—takes place in acetone to yield 85% of diacetone-L-sorbose in the presence of heteropoly acids H3PW12O40 and H4SiW12O40 (0.1–0.35%) as catalysts.
L-— L- — -L- 85% 0.1–0.35% H3PW12O40 H4SiW12O40 .相似文献
15.
The seeds ofCheiranthus allioni hort. have yielded three new cardenolides the structures of which have been established and which have been named as 4-dehydrosarmentogenin (II), 4-dehydrosarmentogenin rhamnoside (I), and 4-dehydrosarmentogenin rhamnoglucoside (IV). (II) — C23H32O5. m.p. 296–302°, []
D
20
+26.2±3° (in pyridine) is 3,11,14-trihydroxy-14-card-4,20(22)-dienolide. (I) C29-H42O9, m.p. 268–275°, []
D
20
–38.2±3° (chloroform-ethanol) is 11,14-dihydroxy-3--L-rhamnopyranosyloxy-14-card-4,20(22)-dienolide.(IV) C35H52O14, []
D
20D
–44.1±3° (methanol), is 3-(4-O--D-glucopyranosyl--L-rhamnopyranosyloxy)-14-card-4, 20(22)-dienolide. An independent synthesis of 4-dehydrosarmentogenin (II) has been carried out, starting from 3,5,11,14-tetrahydroxy-5,14-card-20(22)-enolide, which has confirmed its structure.For Communication XI, see [1].All-Union Scientific-Research Drug Institute, Kharkov. Kharkov State Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 119–125, January–February, 1987. 相似文献
16.
von Niessen Wolfgang Cederbaum Lorenz S. Kraemer Wolfgang P. 《Theoretical chemistry accounts》1977,44(1):85-93
The vertical valence ionization potentials of cyclopropane, ethylene oxide and ethylene imine are calculated by a many-body Green's function method. For C3H6 the ordering of the ionization potentials is 2e(), 1e(), 2a1(), 1a2(), 1e(). The assignment of the 2a1 and the 1a2 ionization potentials which has been controversial is thus clarified. The ordering is in agreement with the result obtained via Koopmans' theorem. For ethylene oxide and ethylene imine Koopmans' theorem fails in predicting the correct order of ionic states. For C2H4O the ordering of the ionization potentials is 2b
1(), 4a
1, 1a
2(), 2b
2,3a
1, 1b
1(), 1b
2, 2a
1 and for C2H5N 6a, 5a, 3a, 2a, 4a, 3a, 1a, 2a. The agreement of the computed ionization potentials with the experimental values is very satisfactory. 相似文献
17.
L. I. Kuznetsova M. A. Fedotov E. N. Yurchenko 《Reaction Kinetics and Catalysis Letters》1989,39(2):393-398
In aqueous solution, PM12–nVnO40
–(3+n) (M=Mo,W) hetero-polyanions provide a much faster oxidation of NO than mononuclear VO
2
+
ions, yielding HNO2, NO
3
–
and reduced HPA.
, PM12–nVnO40 –(3+n) (M=Mo,W) , VO 2 + , NO HNO2 NO 3 – .相似文献
18.
V. V. Shereshovets N. M. Korotaeva Yu. I. Puzin G. V. Leplyanin V. D. Komissarov 《Reaction Kinetics and Catalysis Letters》1990,42(1):39-46
Kinetic regularities in the reaction of triphenyl phosphite ozonide with several thioacetals in CH2Cl2 solution at –15°C have been studied. The consumption rate of ozonides is described by the kinetic equation W=k0[(C6H5O)3P·O3]+k1[(C6H5O)3P·O3][R1R2C(SR3)2] Rate constants k0 and k1 for the thioacetals: (CH3H7S)2CH2, (C6H5S)2CH2, (C6H5CH2S)2CH, (n=C12H25–S)2CH2, (C3H7S)2C(H)CH3, (C3H7S)2C(H)C6H5, (C3H7S)2C(CH3)C6H5 and (C3H7S)2C(H)C10H9, increases with increasing the electron-donating power of subtituents Ri.
CH2Cl2 –15°C. : W=k0[(C6H5O)3P·O3]+k1[(C6H5O)3P·O3][R1R2C(SR3)2] k0 k1 (C3H7S)2CH2, (C6H5S)2CH2, (C6H5CH2S)2CH2, (n-C12H25S)2CH2, (C3H7S)2C(H)CH3, (C3H7S)2C(H)C6H5, (C3H7S)2C(CH3)C6H5, (C3H7S)2C(H)C10H9. .相似文献
19.
Reduction of V2O5/Al2O3 and V2O5/silica-alumina produced Lewis acid sites which could strongly adsorb CO (heat of adsorption: 90 kJ/mol). Such strong acid sites were not formed in the cases of V2O5/SiO2 and V2O5/MgO. V2O5 loaded on Al2O3 interacted with the basic sites of alumina but not with the acidic sites, while the V2O5 on silica-alumina interacted with the acidic sites of the silica-alumina and decreased its acidity.
V2O5/Al2O3 V2O5/SiO2–Al2O3 , CO ( 90 /). V2O5/SiO2 V2O5/MgO . V2O5, Al2O3, , , V2O5 SiO2–Al2O3 - .相似文献
20.
A. Venkataraman V. A. Mukhedkar A. J. Mukhedkar 《Journal of Thermal Analysis and Calorimetry》1989,35(7):2115-2124
Iron(II) tartrate two and a half hydrate (FeC4H4O6·2.5H2O) was prepared and its thermal dehydration and decomposition were studied with a simultaneous thermal analyser (TG/DTA/DTG) under atmospheres of static air, dynamic dry nitrogen and dynamic air. This study was supplemented with the two-probe d.c. electrical conductivity technique under the same atmospheres. Under all the above atmospheres, the thermal dehydration was found to be a two-step process. However, the thermal decomposition process was quite complicated, involving the formation of various metastable intermediates, including-Fe2O3. The final product of decomposition under all atmosphere was-Fe2O3.Studies on the physical properties of-Fe2O3 were also undertaken.
Now deceased.
Financial assistance for this work was given by Grants-in-aid (Defence Ministry), Govt. of India. One of the authors (A.V.R.) is grateful to the Head, Dept. of Chemistry, Sardar Patel University, for his interest and encouragement. 相似文献
Zusammenfassung Es wurde Eisen(II)-tartrathydrat (FeC4H4O6 · 2,5H2O) hergestellt und seine thermische Dehydratation bzw. Zersetzung in statischer Luftatmosphäre bzw. im Stickstoff- und Luftstrom mittels eines Simultanthermoanalysators (TG/DTA/DTG) untersucht, ergänzt durch Untersuchungen nach dem Gleichstromleitfähigkeitsverfahren in den gleichen Atmosphären. Die thermische Dehydratation wurde in jedem Falle als zweistufig befunden. Der thermische Zersetzungsprozeß ist jedoch wegen der Bildung verschiedener metastabiler Zwischenprodukte, z. B.-Fe2O3, recht kompliziert. Das Endprodukt der Zersetzung war in allen Fällen-Fe2O3. Weiterhin wurden die physikalischen Eigenschaften von-Fe2O3 untersucht.
, FeC4H4O6 · 2,52. . , . , y-Fe2O3. -Fe2O3. -Fe2O3.
Now deceased.
Financial assistance for this work was given by Grants-in-aid (Defence Ministry), Govt. of India. One of the authors (A.V.R.) is grateful to the Head, Dept. of Chemistry, Sardar Patel University, for his interest and encouragement. 相似文献