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151.
Manfred Meisel Annegrit Rabis Arnd-Rüdiger Grimmer Irmgard Hartwich Regina Bienert Dirk Wulff-molder 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Previoudy we reported on the preparative use of donorstabilized monometaphosphates, Py.PO2Cl and Py.PS2Cl[1]. 3P MAS investigations as well as X-ray single crystal analysis have been carried out. The isotropic chemical shift of the sulfur compound shows the typical downfield shift (106 ppm) with respect to the oxygen compound The chemical shift anisotropy gives additional information. The relative large spans ω (Py.PO2Cl: 401 ppm, Py.PS2Cl: 461 ppm) [2] reveal strong deviations from tetrahedral symmetry (ω = 0 ppm) in agreement with the structural data. The values of the skew parametem K (0.64 and 0.71 resp.) reflect the trend to axial symmetry (k = ± l). X-ray diffraction and NMR data suggest a structural model corresponding to a concentration of double bond character on the two P-X bonds. This model is consistent with the extremely short P-X bond length (1.449 Å and 1.921 Å rasp.) as well as the large P-X-P bond angles (126.4°and 123.7° resp.). 相似文献
152.
Manfred Scheer Peter Kramkowski Michael Schiffer Jan Müller 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):717-720
Herein we report the synthesis of different phosphido-complexes and -intermediates with WLE-triple bond. These compounds reveal different reactivity patterns. Details of reactivity as well as spectroscopic and theoretical aspects will be discussed in detail. 相似文献
153.
154.
155.
Ying Su Christos S. Karamitros Julian Nomme Theresa McSorley Manfred Konrad Arnon Lavie 《Chemistry & biology》2013,20(4):533-540
Highlights? Increased expression of hASNase3 was observed in several tumors, but the relevance is unclear ? Cancer cells have increased glycolytic flux and thus have more glycine but less aspartate ? Glycine activates the asparaginase activity of hASNase3 by promoting self-cleavage ? Thus, glycine may act as a sensor that regulates cellular aspartate concentrations 相似文献
156.
Manfred Rätzsch Gottfried Haudel Gisela Pompe Evelyn Meyer 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(13-14):1631-1655
157.
Manfred Gerken Sabine Blank Cenek Kolar Peter Hermentin 《Journal of carbohydrate chemistry》2013,32(2):247-254
Abstract 10-O-(R/S)Tetrahydropyranosyl-β-rhodomycinone (5a,b) was prepared via 7,9-O-phenylboronyl-β-rhodomycinone (3) from β-rhodomycinone (1). Glycosidation of 5a,b with 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol (3,4-di-O-acetyl-L-rhamnal) (6) and 3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-L-lyxo-hex-1-enitol (3,4-di-O-acetyl-L-fucal) (7) using N-iodosuccinimide gave the corresponding 7-O-glycosyl-β-rhodomycinones 8a,b, 9a,b and 10a,b, 11a,b. After cleavage of the THP-ether and O-deacetylation 7-O-(2,6-dideoxy-2-iodo-α-L-manno-hexopyranosyl)-β-rhodomycinone (14) and 7-O-(2,6-dideoxy-2-iodo-α-L-talo-hexopyranosyl)-β-rhodomycinone (16) were obtained. 相似文献
158.
Manfred Regitz Wolfgang Rösch Thomas Allspach Ulrich Annen Karsten Blatter Jürgen Fink 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):479-482
Abstract The syntheses of phospholes (7, [3+2]-cycloaddition), bicyclophosphaalkenes (17, [4+2]-cycloaddition), and phosphabenzenes (15, [4+2]-cycloaddition followed by an extrusion process) starting from the phosphaalkynes (4) are described. The 2–Dewar phosphabenzene 18, obtained from the cyclobutadiene 21 and 4 (R =tBu), is the starting material for the synthesis of the valency isomers 19, 20, 22, and 23. 相似文献
159.
Multianalytical Study of Patina Formed on Archaeological Metal Objects from Bliesbruck-Reinheim 总被引:1,自引:0,他引:1
Michael Wadsak Ina Constantinides Guido Vittiglio Annemie Adriaens Koen Janssens Manfred Schreiner Freddy C. Adams Philippe Brunella Michel Wuttmann 《Mikrochimica acta》2000,133(1-4):159-164
Patinas naturally formed on archaeological bronze alloys were characterized using light microscopy (LM), micro energy dispersive
X-ray fluorescence analysis (μ-EDXRF), time of flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscopy
in combination with energy dispersive X-ray microanalysis (SEM/EDX). The examinations carried out on cross-sections of samples
have shown that in all samples the copper content in the corrosion layer is lower than in the bulk, while an increase of tin
and lead could be observed. Two different types of corrosion were found: first type, a corrosion formation leading to a three
layer structure was observed on lead bronze. The outer layer consists mainly of Cu(II) compounds and soil material, followed
by a fragmented layer of cuprous oxide and the surface layer of the alloy, where a depletion of copper and an enrichment of
tin and high amounts of Cl could be detected. The second type of corrosion is characterized by a two layer structure on the
tin bronze sample consisting of an outer layer with copper containing corrosion products and a layer with cracks, which reveals
a depletion of copper whereas tin and lead are enriched. Also high amounts of Si were detected in this surface layer. 相似文献
160.
Treatment of lead(II) bromide with phenylmagnesium bromide at low temperature furnishes yellow crystals of the ionic compound [BrMg(THF)5]+ [:Pb(PbPh3)3]- which, upon X-ray crystallographic analysis, reveals three stretched Pb-Pb bonds and Pb-Pb-Pb angles of about 93 degrees. 相似文献