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61.
Martha CT van Zeist WJ Bickelhaupt FM Irth H Niessen WM 《Journal of mass spectrometry : JMS》2010,45(11):1332-1343
Ferrocene is a popular template in material science due to its exceptional characteristics that offer the ability to optimize the selectivity and activity of catalysts by the addition of carefully selected substituents. In combinatorial catalyst development, the high susceptibility to electrophilic substitution reactions offers the opportunity for the rapid introduction of molecular diversity. Mass spectrometry (MS)-based continuous-flow systems can be applied to rapidly evaluate catalyst performance as well as to (provisionally) identify the introduced catalyst complexes. Herein, we describe the fragmentation characteristics of the [ferrocenyl bidentate + Ag](+) catalyst complexes in dedicated (high-resolution) MS(n) experiments. The investigation of the fragmentation patterns of a selected number of catalyst classes is accompanied with a density functional theory investigation of fragmentation intermediates in order to assess the viability of a selected fragmentation mechanism. 相似文献
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Wilfried N?rtersh?user 《Hyperfine Interactions》2011,199(1-3):131-140
An overview on laser spectroscopic work on highly charged ions (HCI) currently performed or in preparation at GSI is given. This includes laser spectroscopy on HCI in ion traps at the HITRAP facility and at the experimental storage ring (ESR). 相似文献
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This document describes the homogenization of a folded sandwich core. By using a numerical homogenization concept the components of the elasticity tensor of the foldcore continuum are determined. The foldcore exhibits an effective orthotropic behaviour with the particularity that it can be auxetic. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Martin Giera Jon S. B. de Vlieger Henk Lingeman Hubertus Irth Wilfried M. A. Niessen 《Rapid communications in mass spectrometry : RCM》2010,24(10):1439-1446
Structural elucidation of six regioisomers of mono‐N‐octyl derivatized neomycin is achieved using MSn (up to n = 4) on an ion trap time‐of‐flight (IT‐TOF) instrument equipped with electrospray ionization. The mixture of six derivatized neomycin analogues was generated by reductive amination in a shotgun synthetic approach. In parallel to the liquid chromatography/mass spectrometry (LC/MS) detection, the antibacterial activity of the neomycin regioisomers was tested by post‐column addition of buffer and bacterial inocula, subsequent microfractionation of the resulting mixture, incubation, and finally a chemiluminescence‐based bioactivity measurement based on the production of bacterial ATP. The MS‐based high‐resolution screening approach described can be applied in medicinal chemistry to help in designing and producing new antibiotic substances, which is particularly challenging due to the high functionality of most antibiotic substances, therefore requiring advanced (hyphenated) separation and detection techniques for compound mixtures. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Summary Disilane derivatives undergo disproportionation reactions to polysilanes. Investigated were 1,2-dimethyldisilane and 1,2-dimethyltetrachlorodisilane with catalysts like NH4Cl, AgCN, and Nacyanamide. In case of 1,2-dimethyldisilane, with more than catalytic amounts of NH4Cl, a nitrogen containing polysilane is formed. Two new compoundsMeSiH(NCO)2 andMe
2Si2(NCO)4 were synthesized and characterized. The last one leads to a polymer at heating. Additionally an electrochemical formation of polydimethylsilane is described. 相似文献
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Complexity measures for sequences over finite fields, such as the linear complexity and the k-error linear complexity, play an important role in cryptology. Recent developments in stream ciphers point towards an interest in word-based stream ciphers, which require the study of the complexity of multisequences. We introduce various options for error linear complexity measures for multisequences. For finite multisequences as well as for periodic multisequences with prime period, we present formulas for the number of multisequences with given error linear complexity for several cases, and we present lower bounds for the expected error linear complexity. 相似文献