Bernd Enthaler  Tanja Bussmann  Julia K. Pruns  Claudius Rapp  Markus Fischer  Jens‐Peter Vietzke 《Rapid communications in mass spectrometry : RCM》2013,27(8):878-884

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Siengalewicz P  Gaich T  Mulzer J 《Angewandte Chemie (International ed. in English)》2008,47(43):8170-8176

The communesin/nomofungin/perophoramidine story is an impressive example of how biogenetic considerations can lead to the correction of structural misassignments and inspire synthetic chemists with new, fruitful ideas. Intensive studies by a number of research groups culminated in the total synthesis of perophoramidine by the Funk research group in 2004. In 2007, Qin and co-workers completed the first total synthesis of a communesin.  相似文献   

    

Kasia Kieltyka  Jun Zhang  Shu Li  Marianne Vath  Chris Baglieri  Cheryl Ferraro  Tatyana A. Zvyaga  Dieter M. Drexler  Harold N. Weller  Wilson Z. Shou 《Rapid communications in mass spectrometry : RCM》2009,23(11):1579-1591

Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the bioanalytical method of choice to support plate‐based, in vitro early ADME (Absorption, Distribution, Metabolism and Excretion) screens such as metabolic stability (Metstab) assessment. MS/MS method optimization has historically been the bottleneck in this environment, where samples from thousands of discrete compounds are analyzed on a monthly basis, mainly due to the lack of a high‐quality commercially available platform to handle the necessary MS/MS method optimization steps for sample analysis by selected reaction monitoring (SRM) on triple quadrupole mass spectrometers. To address this challenge, we recently developed a highly automated bioanalytical platform by successfully integrating QuickQuan? 2.0, a unique high‐throughput solution featuring MS/MS method optimization by automated infusion, with a customized in‐house software tool in support of a Metstab screen. In this platform, a dual‐column setup running parallel chromatography was also implemented to reduce the bioanalytical cycle time for LC/MS/MS sample analysis. A set of 45 validation compounds was used to demonstrate the speed, quality and reproducibility of MS/MS method optimization, sample analysis, and data processing using this automated platform. Metstab results for the validation compounds in microsomes from multiple species (human, rat, mouse) showed good consistency within each batch, and also between batches conducted on different days. We have achieved and maintained a monthly throughput of 1300 compound assays representing 500 discrete compounds per instrument per month on this platform, and it has been used to generate metabolic stability data for more than 25 000 compounds to date with an overall success rate of more than 95%. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

    

Friederike Schmid  Guido Germano  Stefan Wolfsheimer  Tanja Schilling 《Macromolecular Symposia》2007,252(1):110-118

Summary: We review and compare recent work on the properties of fluctuating interfaces between isotropic and nematic liquid-crystalline phases. Molecular dynamics and Monte Carlo simulations have been carried out for systems of ellipsoids and hard rods with aspect ratio 15:1, and the fluctuation spectrum of interface positions (the capillary wave spectrum) has been analyzed. In addition, the capillary wave spectrum has been calculated analytically within the Landau-de Gennes theory. The theory predicts that the interfacial fluctuations can be described in terms of a wave vector dependent interfacial tension, which is anisotropic at small wavelengths (stiff director regime) and becomes isotropic at large wavelengths (flexible director regime). After determining the elastic constants in the nematic phase, theory and simulation can be compared quantitatively. We obtain good agreement for the stiff director regime. The crossover to the flexible director regime is expected at wavelengths of the order of several thousand particle diameters, which was not accessible to our simulations.  相似文献   

    

Martin Schlupp  Tanja Weil  Alexander J. Berresheim  Uwe M. Wiesler  Joachim Bargon  Klaus Müllen 《Angewandte Chemie (International ed. in English)》2001,40(21):4011-4015

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Harold Boerrigter  Tanja Tomasberger  Willem Verboom  David N. Reinhoudt 《European journal of organic chemistry》1999,1999(3):665-674

Cavitands with phosphane sulfide moieties 4 and 8a , b were prepared in good yields from their phosphane oxide analogues, as more stable alternatives for the dithiophosphinic acids used at present. The cavitands 7a and 7b with flexible butoxyphosphane oxide ligating sites are more efficient than cavitand 3 having rigid methylphosphane oxide groups as was studied with Eu^III picrate extractions. Due to the absence of an ionic functionality in the phosphane sulfides 4 and 8a , b Am^III and Eu^III are not extracted, not even in the presence of synergents (e.g. TBP , TOPO , HDNNS ). Cavitand 10 with phosphinic acid groups efficiently extracts Eu^III in 1:1 or 2:1 complexes, depending on the metal-to-ligand concentration ratio (extraction constants K_ex¹ = 3.9·10^–5M ² and K_ex² = 1.9·10²M , respectively). Furthermore, in the case of 10 Eu^III is preferentially extracted over Am^III with a separation factor S_Eu/Am up to 5.  相似文献   

    

Wolfgang Petz  Frank Weller  Fritjof Schmock 《无机化学与普通化学杂志》1998,624(7):1123-1129

The Reactions of CH₂=P(NMe₂)₃ with Fe(CO)₅, Cr(CO)₆, and CS₂; Molecular Structures of [MeP(NMe₂)₃][(CO)₅CrC(O)CH=P(NMe₂)₃], and (CO)₄Fe=C(OMe)CH=P(NMe₂)₃ The ylide CH₂=P(NMe₂)₃ ( 1 ) reacts with several binary transition metal carbonyls M(CO)_x to produce the corresponding salt like compounds [MeP(NMe₂)₃][(CO)_x–1MC(O)CH=P(NMe₂)₃] (M = Fe ( 3 ), Cr ( 4 )). The related reaction with CS₂ leads to the salt [MeP(NMe₂)₃][SC(S)CH=P(NMe₂)₃] ( 2 ). While 4 is thermally stable, 3 rapidly decomposes at room temperature with formation of [MeP(NMe₂)₃]₂[Fe₂(CO)₈] ( 8 ). Alkylation of 3 (at –50 °C) and 4 with MeSO₃CF₃ produces the related carbene complexes (CO)_x–1M=C(OMe)CH=P(NMe₂)₃ ( 5 ) and ( 6 ); the reaction of 3 with Me₃SiCl results in the formation of the carbene complex (CO)₄Fe=C(OSiMe₃)CH=P(NMe₂)₃ ( 7 ). 4 crystallizes in the space group P2₁2₁2₁ (No. 19) with a = 1111.1(2), b = 1476.1(3), c = 1823.1(4) pm and Z = 4. 5 crystallizes in the space group P2₁/n (No. 14) with a = 1303.6(3), b = 910.5(4), c = 1627.0(4) pm, β = 96.06(2)° and Z = 4. The compounds have been characterized by elemental analyses, NMR (¹H, ¹³C, ³¹P) and IR spectroscopy.  相似文献   

    

Andrew L. Hector  Eric G. Hope  William Levason  Mark T. Weller 《无机化学与普通化学杂志》1998,624(12):1982-1988

XAS at the nickel K-edge and UV-visible studies of rhombohedral nickel trifluoride indicate that the compound has a mixed valence composition Ni[NiF₆] and is isostructural with Pd[PdF₆]. XAS data are reported for NiF₂, [NiF₆]^2–, [NiF₆]^3–, Pd[PdF₆], CoF₃ and RhF₃ in support of the Ni[NiF₆] study. New data from refinements of X-ray powder diffraction of CoF₃ and IrF₃ are reported in the context of the distortion from hexagonal close packing of rhombohedral trifluorides.  相似文献   

    

Paul F. Henry  Mark T. Weller 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1998,110(20):3040-3041

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Michael Kampf  Rainer Richter  Jan Griebel  Anke Weller  Reinhard Kirmse 《无机化学与普通化学杂志》2005,631(4):698-708

Synthesis, Structures, EPR and ENDOR Investigations on Transition Metal Complexes of N, N‐diisobutyl‐N′‐(2, 6‐difluoro)benzoyl selenourea The synthesis and the structures of the Ni^II and Pd^II complexes of the ligand N, N‐diisobutyl‐N′‐(2, 6‐difluoro)benzoylselenourea HBuⁱ₂dfbsu are reported. The ligands coordinate bidentately forming bis‐chelates. The structure of the ligand could not be obtained, however, the structure of its O‐ethyl ester will be reported. Attempts to prepare the Cu^II complex result only in the formation of oily products. However, the Cu^II complex could be incorporated into the corresponding Ni^II and Pd^II compounds. From this diamagnetically diluted powder and single‐crystal samples were obtained being suitable for EPR‐ENDOR measurements. We report X‐ and Q‐band EPR investigations on the systems [Cu/Ni(Buⁱ₂dfbsu)₂] and [Cu/Pd(Buⁱ₂dfbsu)₂] as well as a single‐crystal X‐band EPR study for [Cu/Ni(Buⁱ₂dfbsu)₂]. The obtained ^{63, 65}Cu and ⁷⁷Se hyperfine structure tensors allow a determination of the spin‐density distribution within the first coordination sphere. In addition, orientation selective ¹⁹F Q‐band pulse ENDOR investigations on powder‐samples of [Cu/Ni(Buⁱ₂dfbsu)₂] have been performed. The hyperfine structure tensors of two intramolecular ¹⁹F atoms could be determined. According to the small ¹⁹F couplings only a vanishingly small spin‐density of < 1 % was obtained for these ¹⁹F atoms.  相似文献