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Reactions of π-Organonickel Complexes with Tertiary Phosphanes In a hexane solution Ni(C5H5)2 reacts with PBu3 or Ph2PBu forming the nickel(O) complexes Ni(PBu3)4 or Ni(Ph2PBu)4 (A). Under the same conditions only one cyclopentadienyl ligand is substituted by PhPBu2 and the nickel(I) compound (C5H5)Ni (PhPBu2)2 (B) is obtained. Products of the reactions between B and α,α′-dipyridyl, hydrogen chlorid in ether, or Ni(PhPBu2),Cl2 are Ni(dipy)2, [PhPHBu2]2[NiCl4], or (C5H5) Ni(PhPBu2)2Cl. By the reaction with HgCl2 a cyclopentadienyl compound of an unknown structur is formed. The compound Ni(PhPBu2)4 which is analogous to A is synthesized by the reduction of bis(acety1acetonato)-nickel with Et2AlOEt in the presence of PhPBu2 or by the reaction of bis (cyclooctadiene-1,5)-nickel with PhPBu2. 相似文献
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The mass spectra of the pyrrolidides of some long-chain carboxylic acids with alicyclic residues attached to their ω-end are discussed and compared with the spectra of the corresponding esters. Fragmentation triggered by the pyrrolidide group generates a series of peaks, which clearly exhibits the size and the structure of the carbon chain. 相似文献
6.
Sten Andersson Christofer Leygraf Torsten Johnsson 《Journal of solid state chemistry》1975,14(1):78-84
The nature of the defect structure of Ru4Si3 has been studied with electron diffraction and electron microscopy methods. Lattice image pictures, interpreted with histogram analysis, reveal that planar defects of chemical twinning type are common in the crystals. 相似文献
7.
Walther Lamprecht und Hubert Katzlmeier 《Fresenius' Journal of Analytical Chemistry》1961,181(1):216-229
Zusammenfassung An kristallisierten Enzymen des biologischen Stoffwechsel wird gezeigt, daß bei der Polarographie nur die schwefelhaltigen Proteine katalytische Wasserstoffwellen geben. Von den in der Literatur beschriebenen Doppelstufen der Proteine besitzt nur die im negativeren Potentialbereich liegende Welle die eigentliche katalytische Funktion. Die erste Vorwelle von Proteinen verschwindet, wenn die polarographische Messung bei 0° C durchgeführt wird.In Proteinen sind nur Disulfidgruppen katalytisch wirksam. Sogenannte reine Sulfhydryl-Enzyme haben keinen katalytischen Effekt. Typische SH-Enzyme können jedoch polarographisch als p-Chloromercuribenzoatkomplexe gemessen werden.Durch Harnstoffzusatz bei der polarographischen Messung von Proteinen gelingt es, zwischen maskierten und freien Sulfhydryl- oder Disulfidgruppen an Enzymen zu definieren.Auszug aus der Dissertationsschrift H. Katzlmeier, Technische Hochschule München (1959). 相似文献
8.
Klaus Burger Elisabeth Windeisen Elisabeth Heistracher Torsten Lange Abdel-Aleem H. Abdel-Aleem 《Monatshefte für Chemie / Chemical Monthly》2002,2(3):41-58
The synthesis of homochiral heterocyclic α-hydroxy acids starting from (S)- and (R)-malic acid using hexafluoroacetone as protecting and activating agent is described. The new compounds are useful building
blocks for peptide and depsipeptide modification. 相似文献
9.
The stabilities of the complexes formed by silver(I), cadmium(II) and zinc(II) with tri-n-butylamine and tri-n-butylphosphine have been determined in dimethyl sulfoxide (DMSO). For the two latter metal ions, it has also been found that complexes are not formed in appreciable amounts with the triphenyl compounds Ph3X, X = N, P and, in the case of cadmium(II), also As.From these and earlier measurements referring to DMSO as well as aqueous solutions, it was found that the stepwise stability constants increase by roughly one power of ten for each aromatic ring replaced by an aliphatic group, evidently as a consequence of the improved donor properties of the coordinating atoms. Further, for ligands of the same type, the stabilities are always markedly lower in DMSO than in aqueous solution. This is certainly due to the fact that the solvent molecules compete more strongly for the coordination sites in DMSO than in water, as reflected by the larger heats of solvation found in the former solvent for the metal ions concerned. 相似文献
10.
Torsten Barfels Bernd Schmidt Andreas von Czarnowski Hans-Joachim Fitting 《Mikrochimica acta》2002,139(1-4):11-16
For investigation of the luminescent center profile cathodoluminescence measurements are used under variation of the primary
electron energy E
0 = 2…30 keV. Applying a constant incident power regime (E
0·I
0 = const), the depth profiles of luminescent centers are deduced from the range of the electron energy transfer profiles dE/dx.
Thermally grown SiO2 layers of thickness d = 500 nm have been implanted by Ge+-ions of energy 350 keV and doses (0.5–5)1016 ions/cm2. Thus Ge profiles with a concentration maximum of (0.4 – 4) at% at the depth of dm≅240 nm are expected. Afterwards the layers have been partially annealed up to T
a = 1100 °C for one hour in dry nitrogen. After thermal annealing, not only the typical violet luminescence (λ = 400 nm) of
the Ge centers is strongly increased but also the luminescent center profiles are shifted from about 250 nm to 170 nm depth
towards the surface. This process should be described by Ge diffusion processes, precipitation and finally Ge nanocluster
formation. Additionally, a Ge surface layer is piled-up extending to a depth of roughly 25 nm. 相似文献