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1.
Summary Benzoylacetone isonicotinoyl hydrazone has been prepared in two forms: yellow (BzH2) and white (BzH2·H2O). Analytical, t.g.a., i.r. and n.m.r. results showed the yellow form to be a mixture of keto-enol tautomers, whereas the white form is a mixture of cis-trans enol tautomers. Complexes MBz (M = Ni, Cu, Zn and Pd), CoBz·H2O and Cd(BzH)2 have been isolated and characterized by physicochemical techniques. 相似文献
2.
Mohamed Hilmy Elnagdi Ramadan Maawad Abdel-Motaleb Mona Mustafa Mohamed Foad Zayed Eman Moustafa Kamel 《Journal of heterocyclic chemistry》1987,24(6):1677-1681
The behaviour of several 2-amino-3-cyano-4H-pyran derivatives toward a variety of nucleophilic reagents is reported. 相似文献
3.
If F ? ? is a closed set such that the space of all Whitney jets on F admits an extension operator then there exists such an extension operator whose values are holomorphic in ?F if and only if ?F is compact. In the case F is a compact set, there is even an extension operatorfor which the extensions are holomorphic in (? ∪ {∞})F. 相似文献
4.
We use the PCP-SAFT equation of state, which is of the Van der Waals type and has a sound physical basis, to predict mixture properties, such as vapor–liquid and liquid–liquid equilibria, as well as excess enthalpies. We use molecular properties, such as dipole moment, quadrupole moment, polarizability and dispersion interaction coefficients, that have been determined quantum mechanically in Part I of this publication and adjust the remaining three pure compound parameters to pure compound data. We finally present a new combination rule for the dispersion energy parameter ? that is based on the quantum mechanically determined data. The predictions based on quantum mechanically determined pure compound properties along with the new combination rule show an improved performance compared to the original PCP-SAFT combination rule. 相似文献
5.
Image potential resonances on the Sn/Ge(1 1 1) α-phase are investigated by two closely related methods: specular electron reflection and so-called selective electron scattering. Electrons from image resonances are detected on this surface at 120 and 300 K, i.e. below and above the phase transition at about 200 K. The dispersion of the image resonances reveals at these two temperatures equivalent effective electron masses, which are characteristic for this type of electronic surface states. The results of the two methods are consistent according to the similarity of the scattering processes. Changes in the loss peak intensity with the annealing temperature are assigned to the surface quality and are reflected by characteristic photoemission intensities. 相似文献
6.
The reactions between rubidium carbonate and vanadium pentoxide were performed at different high temperatures. Four reaction products of the compositions: I. Rb2O · V2O5; II. 2 Rb2O · V2O5; III. 3 Rb2O · V2O5; and IV. Rb2O · 4 V2O5 were obtained. According to the determination of Rb and the X-ray powder photographs of the products the existence of rubidium metavanadate (RbVO3) and rubidium pyrovanadate (Rb4V2O7) was confirmed. On the other hand, the preparation of a pure rubidium orthovanadate (Rb3VO4) and rubidium tetravanadate (Rb2O · 4 V2O5) was not successful. The diffraction pattern of Rb2O · V2O5 obeys hexagonal indexing with lattice dimensions a = 7.347 and c = 13.608 Å. 相似文献
7.
Khalil MM Mohamed HA El-Medani SM Ramadan RM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(6):1341-1347
Reaction of Cr(CO)(6) with 2-(2'-pyridyl)benzimidazole (pbiH) under reduced pressure resulted in the formation of the dinuclear complex [Cr(2)(CO)(6)(pbiH)(2)]. Infra-red (IR) spectroscopy revealed the presence of terminal and bridge Cr-CO bonds. Interaction of M(CO)(6), M=Cr, Mo and W, with pbiH in the presence of 2,2'-bipyridine (bpy) gave the tetracarbonyl complexes [M(CO)(4)(pbiH)].bpy. Spectroscopic studies of the complexes indicated the presence of hydrogen bonding between the bpy nitrogen and the NH group of pbiH. Reactions of M(CO)(6) with pbiH in the presence of PPh(3) gave the tricarbonyl monosubstituted derivatives [M(CO)(3)(PPh(3))(pbiH)]. The spectroscopic studies of the complexes suggested the proposed structures. 相似文献
8.
A comparison of different nebulisers for direct hyphenation of capillary and nano liquid chromatography (Cap-LC, Nano-LC) and quadrupole-based collision cell inductively coupled plasma mass spectrometry (CC-ICP–MS) for phosphorylation profiling of tryptic protein digests is described. Helium was used as cell gas and specially tuned instrumental conditions were used to achieve background minimisation at the mass of phosphorus, because of kinetic energy discrimination of the interfering polyatomic ions. The proposed set-up is based on a modified capillary electrophoresis interface and a home-made 4 mL spray chamber. It enables the use of gradient conditions with a highly concentrated organic mobile phase as often used in protein phosphorylation analysis, without the need to apply membrane desolvation for removal of the organic phase or further background minimisation. No significant signal suppression or other negative effects caused by the organic mobile phase occur, because of the low flow rates used in Cap-LC and the robust plasma conditions of the CC-ICP–MS instrument. A tryptic digest of beta-casein was investigated as model compound to demonstrate the applicability of the proposed set-up for phosphorylation profiling in protein analysis using quadrupole based collision-cell ICP–MS as phosphorus-specific detector. Detection limits for phosphorylated peptides down to the sub picomole level were obtained. As a complementary technique, electrospray ionisation tandem mass spectrometry (ESI–MS–MS) with data base searching was used for further characterisation of the phosphorylated peptides detected. 相似文献
9.
The preparation and characterization of MnII, FeIII and CuII complexes of three tridentate pyridyl hydrazones are reported.
The ligands were prepared via Schiff base condensation of 6-chloro-2-hydrazopyridine with alpha-formyl-(L1), alpha-acetyl-(L2),
or alpha-benzoyl-(L3) pyridine. The structural characterization of the compounds prepared was based on elemental analyses,
electrical conductance and magnetic moment measurements, 1H-n.m.r., i.r., u.v.-vis. and e.s.r spectroscopic methods. The overall
structure and reactivity of the metal chelates critically depend on the ligand substituents within the carbonyl moiety. Octahedral
and tetrahedral monomeric species were proposed for MnII complexes, and an octahedral environment for the FeIII complexes.
Regarding the copper(II) complexes, a monomeric square-planar and a dimeric structure with a chloride bridge in square-pyramidal
geometry were suggested. In the presence of molecular oxygen, MnII and CuII complexes catalyse the oxidative transformation
of catechol (benzene-1,2-diol) to the corresponding o-benzoquinone. Iron(III) complexes catalyse the aerobic oxidation of
catechol to the intradiol cleavage product. The catalytic activity has been correlated with the Lewis acidity of the metal
centres created according to the nature of the ligand substituents. The probable mechanistic implications of the catalysed
oxidation reactions are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
A. A. T. Ramadan M. S. Abdel-Moez B. A. El-Shetary H. S. Seleim 《Monatshefte für Chemie / Chemical Monthly》1993,124(6-7):647-657
Summary Equilibrium betweenDCPHD,DC-4-Cl-PHD, andDC-4-Me-PHD and protons, transition, and lanthanide ions have been investigated at 30 °C by means of potentiometric titration in 75% (v/v) methanol-water mixture containing 0.10M KNO3 as a constant ionic medium. Thermodynamic parameters (G, H and S) referring to the formation of species HL
–,L
––,ML
+n–2 andML
2
+n–4
(L
–– denotes the ligand anion) have been determined in solutions. The solvent effects on the thermodynamic parameters of the complex formation are discussed in terms of differences in the donor ability of methanol and water solvents. The plots of thermodynamic parameters versus ionic potential (Z
2/r) of the lanthanide elements is not linear as expected from ionic theory. The obtained curve can be resolved in an initial group (the lighter lanthanides), an intermediate group (Sm-Dy), and a final group (the heavier ones, Tb-Lu). This behavior was explained in terms of differences in the dehydration of lighter lanthanide(III) from that of heavier ones.
Thermodynamik der Komplexierung von Lanthaniden und einigen Übergangsmetall-Ionen mit 5,5-Dimethylcyclohexyl-2-(2-hydroxyphenyl)-hydrazono-1,3-dion (DCPHD) und seinen Derivaten
Zusammenfassung Die Gleichgewichte zwischenDCPHD,DC-4-Cl-PHD undDC-4-Me-PHD mit Protonen, Übergangsmetall- und Lanthaniden-Ionen wurden bei 30 °C mittels potentiometrischer Titration in 75% (v/v) Methanol-Wasser mit einem Gehalt an 0.10M KNO3 als konstantem ionischem Medium untersucht. Die thermodynamischen Parameter G, H und S zur Bildung der Spezies HL –,L ––,ML +n–2 undML 2 +n–4 (L –– steht für das Ligandenanion) wurden in Lösung bestimmt. Die Lösungsmitteleffekte auf diese Komplexbildungsparameter werden auf Basis der Differenz im Donorvermögen von Methanol und Wasser als Solventien diskutiert. Die Diagramme der thermodynamischen Parameter gegen die ionischen Potentiale (Z 2/r) der Lanthaniden sind, wie nach der Ionentheorie zu erwarten, nicht linear. Die erhaltene Kurve läßt eine Anfangsgruppe (die leichteren Lanthaniden), eine mittlere Gruppe (Sm-Dy) und eine Endgruppe (die schwereren Lanthaniden. Tb-Lu) erkennen. Dieses Verhalten kann aus dem Unterschied im Dehydratationsverhalten erklärt werden.相似文献