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991.
Summary Be complexes of selected styryl-substituted -diketones were prepared and their absorption, fluorescence, and NMR spectra were measured. The data of these compounds are presented and compared with those of the analogous free ligands and their BF2-complexes. 相似文献
992.
993.
Henrik Ch. Schachner Gustav M. Obermair 《Zeitschrift für Physik B Condensed Matter》1994,95(1):113-119
We have studied quantum properties of right triangular billiards as a function of their acute angle . The energy spectrum and wavefunction plots with the nodal pattern are provided; symmetry arguments are given for regularities found in the classically integrable cases =30° and 45°. A comparison of the level spacing distributions for different confirms the tendency towards level repulsion in the nonintegrable domain. 相似文献
994.
We present predictions for the inclusive production of leptons (e±,μ±) originating from charm and bottom hadrons at the CERN LHC in the general-mass variable-flavour-number scheme at next-to-leading order. Detailed numerical results are compared to data of the CMS, ATLAS and ALICE Collaborations. 相似文献
995.
Proteome research aims to unravel the biological complexity encoded by the genome. Due to the complexity of higher eukaryotic cells, single-step characterization of a proteome is likely to be difficult to achieve. However, advantage can be taken of the macromolecular architecture of a cell, e.g., subcellular compartments, organelles, macromolecular structures and multiprotein complexes, to establish subcellular proteomes. This review highlights recent developments in this area of proteomics, namely the establishment of two-dimensional electrophoresis (2-DE) reference maps of subcellular compartments and organelles as well as the characterization of macromolecular structures and multiprotein complexes using a proteomics approach. 相似文献
996.
Chiral polyesters, end‐capped with terpyridine, were prepared via the coordinative ring‐opening polymerization of L ‐lactide. Stable supramolecular dimer structures resulted after complexation with iron(II) ions. The formation of both the macroligands and the polymer complexes was proven for the first time clearly by means of GPC coupled to an in‐line photodiode array UV/Vis spectrophotometer, NMR spectroscopy and MALDI‐TOF mass spectrometry. A sensitivity of the iron(II)‐centered poly(L ‐lactide)s towards UV irradiation and thermal or pH changes could be observed. 相似文献
997.
Prof. Dr. Gustav Zigeuner Till Strallhofer Franz Wede Walter-Bernd Lintschinger 《Monatshefte für Chemie / Chemical Monthly》1975,106(6):1469-1477
The 3,4-dihydro-3,4,4,6-tetramethyl- and 4,4,6-trimethyl-3-phenyl-2(1H)-pyrimidinethione (1 c, d), resp. as well as the corresponding trimethyl compound1 e are formed byDimroth rearrangement of 2-methylamino- and 2-amino-4,6,6-trimethyl-6H-1,3-thiazine (2 a, b) and of 3,6-dihydro-4,6,6-trimethyl-2-phenylimino-2H-1,3-thiazine (3 b), resp. The rearrangement takes place under thermal heterolysis of the 1–6 bond of2 a, b and3 b. The reactive behaviour1 c, d is almost equal to1 e, but the pyrimidine ring of1 d is more labile than those of1 c, e. 相似文献
998.
New Pentacoordinated Rhodium Species as Unexpected Products during the In Situ Generation of Dimeric Diphosphine‐Rhodium Neutral Catalysts
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Antje Meißner Anja König Dr. Hans‐Joachim Drexler Priv.‐Doz. Dr. Richard Thede Priv.‐Doz. Dr. Wolfgang Baumann Prof. Detlef Heller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14721-14728
Dimeric rhodium complexes of the type [Rh(PP)(μ2‐Cl)]2 (PP=diphosphine) are often used as precatalysts and are generated “in situ” from the corresponding diolefin complexes by exchange of the diene with the desired diphosphine. Herein, we report that the “in situ” procedure also leads to unexpected monomeric pentacoordinated neutral complexes of the type [RhCl(PP)(diolefin)], for the first time herein characterized by NMR spectroscopy and X‐ray crystallography for the ligands 1,4‐bis(diphenylphosphino)propane (DPPP), 1,4‐bis(diphenylphosphino)butane (DPPB), and 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP). The pentacoordinated complexes are in equilibrium with the dimeric target compound [Rh(PP)(μ2‐Cl)]2. The equilibrium is influenced by the rhodium‐diolefin precursor, the solvent and the temperature. Based on the results of NMR and UV/Vis spectroscopic analysis (kinetics) it could be shown that the pentacoordinated complex [RhCl(PP)(diolefin)] may arise both from the “in situ”‐generated neutral complex [Rh(PP)(μ2‐Cl)] by reaction with the free diolefin and, more surprisingly, directly from [Rh(diolefin)(μ2‐Cl)]2 and the diphosphine. 相似文献
999.
D. Schulze W. Heller H. Ullrich H. Kupsch C. Segebade 《Journal of Radioanalytical and Nuclear Chemistry》1993,168(2):385-392
Because of incresing problems due to the general non-acceptance of the application of open radioactivity in modern industrial research an investigation was made concerning the possibility of replacing radiotracers by inactive substances activated by photons after sampling. As an example, investigations in the glass-processing industry was selected. The results were confirmed by the radiotracer experiment performed in parallel. The data obtained were in good agreement. 相似文献
1000.
Spectral polarization features of the macroscopic manifestation of parity violation in gaseous media
Yu. I. Heller 《Optics and Spectroscopy》2006,100(2):152-163
A formalism based on macroscopic Maxwell equations is developed for the case of media with violations of the space symmetry and time reversal. It is demonstrated that the parity violation in a medium is equivalent to the manifestation of spatial dispersion and natural optical activity. The proposed formalism makes it possible to uniquely calculate the macroscopic parameters of equations in terms of the microscopic theory. The parameters of gyrotropy and dichroism of a gaseous medium are determined within a model describing an interaction of resonance radiation with transitions to states that have different parities and are mixed by a weak interaction of an electron with the nucleus of the atom. It is established that, in the range of the resonance with a magnetic dipole transition, the effect of parity violation is enhanced as a result of the considerable difference between the natural broadenings of the electric and magnetic dipole transitions. This enhancement is suppressed when the dominant Doppler broadening of the atomic transitions is taken into account. It is shown that, owing to the unitarity of the weak interaction, the effects of parity violation are alternating functions of the radiation frequency and are integrally absent in the entire spectrum. 相似文献