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111.
Ammonium Chloro(thio)phosphate Betaines, a Class of Coordination-stabilized Chloro(thio)metaphosphates Ammonium chloro(thio)phosphate betaines behave like systems being in equilibrium with tert. amine and monomeric chloro(thio)metaphosphate. In solution at room temperature the amine component can be displaced by stronger donors. Mass spectra reveal the presence of ClPS2 as monomer and dimer, of ClPO2 by fragment ions of the dimer, trimer, and tetramer before reorganization takes place to form PXCl3 and P4X10 (X = O, S). Detection of ClPOS fails owing to fast equilibration into ClPO2 and ClPS2. 相似文献
112.
Organometallic Lewis Acids. XLII. Carbonyl- and Nitrosyl Complexes of Manganese and Rhenium of Weakly Coordinated Anions (Ph3P)2(ON)2MnX, (Ph3P)n(OC)5–nMX (M = Mn, Re; n = 1, 2; X = FBF3, OSO2CF3, OSO2F, OCORf) The complexes (Ph3P)2(ON)2MnX (X = FBF3, OSO2CF3, OSO2F, OCOCF3, OCOC3F7) and (Ph3P)n(OC)5–nMX (M = Mn, Re; n = 1, 2; X = FBF3, OSO2CF3) have been obtained by reaction of (Ph3P)2(ON)2MnH and (Ph3P)n(OC)5–nMeMe with the corresponding acids HX or from (Ph3P)n(OC)5–nReBr (n = 1, 2) with silver salts AgX, respectively. The compounds have been characterized by their IR and partially by 19F-NMR data. An efficient method for the preparation of the hydride (Ph3P)2(ON)2MnH is reported. 相似文献
113.
B. Gillot F. Bouton J.F. Ferriot F. Chassagneux A. Rousset 《Journal of solid state chemistry》1977,21(4):375-385
When Fe3+ ions are substituted by aluminum or chromium on magnetite octahedral sites, the ir spectrum shows the conversion of an inverse spinel to a normal spinel. Both broad bands of magnetite are gradually replaced by the four characteristic bands of normal spinels II–III. They are also observed for solid solutions, FeCr2O4FeAl2O4, with, however, a further band at 780 cm?1 which may be assigned to Al3+ ions on tetrahedral sites. Low-temperature (<400°C) oxidation of these compounds whose sizes are less than 2000 Å results in lacunar spinels III–III. The ir spectrum of these solids is characterized by two absorption bands (as for inverse spinels II–III) except for compounds close to pure γFe2O3 in which an order of vacancies could be put in evidence. 相似文献
114.
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
115.
116.
A miniaturised technique to analyse and detect heterocyclic aromatic amines (HAs) using micro solid-phase extraction (SPE) coupled on-line (in-capillary) to capillary electrophoresis (CE) separation with nanospray (nESI) mass spectrometry (MS) detection has been developed. HAs are mutagenic and carcinogenic compounds formed at low levels in protein-rich food during cooking. Due to the low concentrations of HAs and the high complexity of the matrix in which they exist, sensitive and selective analytical methods are required for quantification. SPE was performed on a packed bed of C18 particles inside the CE capillary, which minimised the dead volume. The on-line coupling of SPE, CE and nESI-MS reduced the time for extraction and identification to less than half an hour, which will allow for screening of several samples per day. The new technique provides short analysis time, low sample and solvent consumption, and HAs in standard solutions were easily detected at 12–17 fmol injections, and in spiked urine samples at 750–810 fmol injections. 相似文献
117.
Two ligand exchange chiral stationary phases (CSPs) based on (S)-leucinol derivative, sodium N-((S)-1-hydroxymethyl-3-methylbutyl)-N-undecylaminoacetate, and (R)-phenylglycinol derivative, sodium N-((R)-2-hydroxy-1-phenylethyl)-N-undecylaminoacetate, covalently bonded to silica gel have been successfully applied in the resolution of nine -hydroxycarboxylic acids. The latter was more effective than the former, the separation factors () being 1.05 to 2.12 while the resolution factors (RS) varying from 0.18 to 5.29 on the latter. The chromatographic resolution behaviors were dependent on the type and the content of organic modifier and the content of CuSO4 in aqueous mobile phase and the column temperature. A possible chiral recognition mechanism was also proposed based on the chromatographic resolution behaviors. 相似文献
118.
Partial molar volumes for a homologous series of amino acids and peptides have been measured in aqueous 1M sodium acetate, sodium thiocyanate, and sodium sulfate at 25°C. These data have been utilized in conjunction with the data in water to deduce partial molar volumes of transfer V
2,m
0(tr) from water to these aqueous salt solutions. The volumes of transfer for the amino acids and peptides are found to be positive. The interpretation is that this result arises from the dominant interaction of the sodium salts with the charged centers of amino acids and peptides. Thermal denaturation of the structurally homologous proteins lysozyme and -lactalbumin has been studied in the presence of these salts. Significant thermal stabilization of hen egg-white lysozyme has been observed in the presence of sodium acetate and sodium sulfate. However, the thermal stabilization observed for -lactalbumin is very small in the presence of these salts and sodium thiocyanate leads to a lowering of its thermal denaturation temperature. The rise in the surface tension of aqueous salt solutions with salt concentration has been correlated with the calorimetric and volumetric measurements. The results show that V
2,m
0(tr) depends less on the type of electrolyte than on the ionic strength of the solution. The V
2,m
0(tr) values correlate very well with the increase in the surface tension of aqueous salt solutions, indicating significant role of surface tension in interactions of amino acids, peptides, or protein with the salts. 相似文献
119.
2,2-Difluoro-1,2,3-trimethyl-1,3-diaza-2λ5-phospholidine The title compound 1 is obtained in about 50% yield by oxidative fluorination of 1,2,3-trimethyl-1,3-diaza-2λ3-phospholidine, 6 , with IF5. 1 is characterized by its nmr, mass, and ir spectra. 相似文献
120.
R. F. Klevtsova L. A. Glinskaya T. E. Kokina S. V. Larionov 《Journal of Structural Chemistry》2003,44(2):256-267
Single crystals of [Ni(Phen)(iBu2PS2)2] (I) and [Ni(Phen)3](iBu2PS2)2 (III) compounds were grown, and their structures were determined by Xray diffraction analysis (CAD4 diffractometer, MoK
radiation, 3336 F
hkl
, R = 0.0373 for I and 2575 F
hkl
for III). The crystals of complex I have a triclinic unit cell with the following parameters: a = 11.097(1) , b = 14.903(2) , c = 22.650(3); = 75.18(1)°, = 80.50(1)°, = 75.07(1)°, V = 3479.2(7)3, Z = 4, calc = 1.255 g/cm3, and space group
1; the crystals of III have a monoclinic unit cell with the following parameters: a = 19.010(3), b = 15.481(1) , c = 17.940(3); = 97.58(1)°, V = 5233.5(12)3, Z = 4, calc = 1.292 g/cm3, and space group C2/c. The structure of complex I is built from mononuclear molecules, and the structure of III, from [Ni(Phen)3]2+ complex cations and i Bu2PS2
- outersphere anions. The NiN2S4 coordination polyhedra in the structure of I and NiN6 in the structure of III are distorted octahedra. Based on structural data, the interaction between the coordinated Phen molecules of complexes I, [Ni(Phen)2(iBu2PS2)](iBu2PS2) (II), and III is considered, as well as the packing modes of these complexes. 相似文献