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1.
The hydrogenation of ethyl 4-R-2,4-dioxobutyrates (R = phenyl, 2-furyl) at 5% Pt/Al2O3 catalyst, modified with cinchonidine, and at palladium black was investigated. The former had low activity under the conditions we tested. The main products during the hydrogenation of these compounds at palladium black are ethyl 4-R-2-hydroxy-4-oxobutyrates. The yield of the phenyl derivative amounts to 68.5%, while the yield of the corresponding 2-furyl derivative amounts to 97%. In the last case ethyl 2-hydroxy-4-oxo-4-(2-tetrahydrofuryl)butyrate was detected as impurity. The optimum conditions for the formation of ethyl 2-hydroxy-4-phenylbutyrate (yield 88.2%) were determined. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 655–659, May, 2006.  相似文献   
2.
Several non-equilibrium solid solutions belonging to the platinum-osmium systems Os0.9Pt0.1, Os0.8Pt0.2, Os0.5Pt0.5, Os0.7Pt0.3, Os0.75Pt0.25 are prepared and studied. The thermal decomposition of [Pt(NH3)4][OsCl6] in the hydrogen and helium atmosphere is investigated. It is found that the Pt0.5Os0.5 solid solution develops through the formation of (NH4)2[OsCl6] and a metallic phase based on Pt. The crystal structure of a double complex salt [Pt(NH3)4][OsCl6] is studied (X8-APEX Bruker, 1508 independent reflections, R = 2.04%). Crystal data for PtOsN4Cl6H12 are: a = 11.6216(5) Å, b = 11.0016(5) Å, c = 10.3819(5) Å, V = 1327.4(1) Å3, space group Cmca, Z = 4, d x = 3.333 g/cm3. The coordination polyhedron around Os is octahedral: 〈Os-Cl〉 2.357 Å, ∠Cl-Os-Cl 89.5–90.5°, while around Pt it is square-planar: Pt-N 2.046 Å, ∠ N-Pt-N 89.59° and 90.41°.  相似文献   
3.
The interactions of [Pt(CNN)(4-dpt)]PF(6), (1; 4-dpt=2,4-diamino-6-(4-pyridyl)-1,3,5-triazine, HCNN=6-phenyl-2,2'-bipyridine) with double-stranded DNA, poly(dA-dT)(2), and poly(dG-dC)(2) were examined by spectroscopic, electrophoretic, and hydrodynamic methods. The spectroscopic data were analyzed with McGhee, van't Hoff, and Gibbs-Helmholtz equations. In a comparative study, [Pt(CNN)(py)]PF(6) (2; py=pyridine) was prepared and the nature of its binding towards DNA was investigated [preliminary results: ChemBioChem 2003, 4, 62-68]. For reactions with calf thymus DNA at 20 degrees C, the intrinsic binding constants for 1 and 2 are (4.6+/-0.2)x10(5) and (2.3+/-0.3)x10(4) mol(-1) dm(3), respectively. Results of DNA-binding reactions revealed that 1 and 2 preferentially bind to the AT sequence of duplex DNA. Intercalation is the preferred binding mode for 2, whereas both intercalation and minor-groove binding are observed for 1. Complex 1 is cytotoxic against a number of carcinoma cell lines, including KB-3-1, CNE-3, and HepG2, and remains potent against multidrug- or cisplatin-resistant KB-V-1 and CNE1 cell lines, for which the resistance ratios are 1.6 and 1.5, respectively. Importantly, 1 is almost an order of magnitude less toxic to the normal cell line CCD-19Lu (IC(50)=176+/-1.7 microM) and it selectively induced apoptosis leading to cancer cell death with less than 5 % detectable necrosis.  相似文献   
4.
5.
Ashok Kumar  M R Gunye 《Pramana》1980,15(5):435-447
The high spin yrast states up toJ=20+ in184, 186Pt and190, 192, 194Pt are studied in a microscopic approach of variation with number-conserved projected states. The energy spectra, quadrupole moments andB(E2) values are calculated by employing the Hamiltonian with quadrupole plus pairing interactions. The results of the calculations are in fair agreement with the available experimental data.  相似文献   
6.
Hydrophobic bimetallic catalysts of Pt-M on styrenedivinylbenzene were prepared, where M represents successively: Ir, Rh, Pd, Cu and Ag. The total metal loading was 0.5 wt% and the weight fractions of the metal M were: 0.0,0.05,0.1,0.25,0.5,0.75 and 1.0. For each sample, the catalytic activity for H/D exchange between hydrogen and water vapor was measured. In case of monometallic catalysts, no activity was detected for M = Cu and M = Ag, and the order of the activity values for the other metals was: Pt < Ir < Rh < Pd. For each bimetallic catalyst, the activity measurements indicated a clear interaction between the platinum and the second metal, thus the activity was significantly increased for M = Ir, increased for M = Rh, decreased for M = Pd, drastically decreased for M = Cu and M = Ag.  相似文献   
7.
The effects of range and geometry of a simple attractive square-well on the phase diagram of hard ellipsoids and hard spherocylinders is systematically studied using a simple van der Waals type theory. The orientational single particle distribution function is approximated using the Onsager trial function. The quantitative errors introduced by this are thought to be considerably smaller than the use of the van der Waals approximation, which has been shown to give qualitatively correct phase diagrams for similar models. The phase diagrams obtained for hard ellipsoids and hard spherocylinders of aspect ratios ranging between 3 and 10 with a variety of square-well attractions are found to fall into three general types. The first type shows liquid-vapour coexistence and an isotropic-nematic transition, which meet at a liquid-vapour-nematic triple point. The second type shows a marked widening of the isotropic-nematic biphasic region which pre-empts the liquid-vapour coexistence. The final phase diagram shows a strong destabilization of the nematic phase with respect to the isotropic, which results in a shift of the phase transition to higher densities and pressures as the temperature is lowered.  相似文献   
8.
In the past five years, a number of d6 complexes have been found to exhibit luminescence when excited by ultraviolet light. Such emission has been assigned to d-d transitions localized on the metal ion, to charge-transfer transitions, and to ligand localized transitions2,3. The specific kind of emission observed is thought to depend on which electronic level lies lowest in energy.  相似文献   
9.
Ein Bericht über die aktivierungsanalytische Bestimmung des Cu, Au, Ir, Os und Ru in Platin durch radiochemische Trennung und gammaspektrometrische Strahlungsmessung. Aufbau eines radiochemischen Trenungsganges durch Verflüchtigung der Tetroxide des Os und Ru, Beseitigung der Matrixaktivität durch Adsorption am Anionenaustauscher, Extraktion des Au, Cu u. a. Elemente als Chloro-, DDTC- und BPHA-Komplexe. Diskussion der Möglichkeiten für den Einsatz des Trennungsganges in der Aktivierungsanalyse. Wiedergabe der Arbeitsvorschrift und der Ergebnisse der Analyse einiger Platinproben mit Verunreinigungen im Bereich von 0,05…400 ppm.  相似文献   
10.
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Elementveruninigungen auch im Spurenbereich (ppm, ppb) becinflussen die Qualität von Halbleiterselen. Bei der Bestimmung interssierender Elemente (Ag, As, Au, Cd, Ga, Sb, Tl) mittles NAA ist mich der Neutronenbestrahlung im Kernreaktor wegen der Störung dutch die entstehende hohe Matrixaktiviät, der Anwesenheit reiner Betastrahler oder infolge Linienüberlagerung im Gammaspektrum im allgemeinen Keine instrumente NAA möglich. Daher müssen nache Zugabe inaktiver Träger und der Matrixabtrennung die interessierenden E-emente durch konventionel-e chemisch-analytische Trennverfahren (Extraktion, Fällung, Ionenaustausch) isoliert warden.  相似文献   
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