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101.
Aequationes mathematicae - 相似文献
102.
103.
Markta Kandrnlov Zoran Kokan Vclav Havel Marek Ne
as Vladimír indel 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18350-18353
Reversible covalent bonds play a significant role in achieving the high‐yielding synthesis of mechanically interlocked molecules. Still, only a handful of such bonds have been successfully employed in synthetic procedures. Herein, we introduce a novel approach for the fast and simple preparation of interlocked molecules, combining the dynamic bond character of bis(acyloxy)iodate(I) anions with macrocyclic bambusuril anion receptors. The proof of principle was demonstrated on rotaxane synthesis, with near‐quantitative yields observed in both the classical and “in situ” approach. The rotaxane formation was confirmed in the solid‐state and solution by the X‐ray and NMR studies. Our novel approach could be utilized in the fields of dynamic combinatorial chemistry, supramolecular polymers, or molecular machines, as well inspire further research on molecules that exhibit dynamic behavior, but owing to their high reactivity, have not been considered as constituents of more elaborate supramolecular structures. 相似文献
104.
In this paper, we develope the new standardization methods to eliminate the influence in capillary electrophoresis (CE). The markers were used to determine the basis position and then correct the data of sample by the migration time of standard sample, and make the migration time of samples consistent with the standard sample by the criterion of the marker. The problem of time transition was corrected in this way. Then according to the peak height or peak area of the marker in the sample (peak height was used here) compared with the standard sample, the sample data was zoomed appropriately. The absorbance error was made to be correct. The wavelet de-noise method was also used to make the data smooth and get a good baseline. 相似文献
105.
A recently discovered anion receptor is jointed by three related macrocycles differing in the number of glycoluril units and type of substitution. The synthesis is carried out in nonpolar solvents compared to aqueous media used in the case of the original macrocycle. The size of macrocycle is controlled by a template. A hexameric macrocycle with benzyl substitution binds halide anions with an affinity exceeding 10(9) M(-1) while a tetrameric analog does not bind any of the investigated anions. 相似文献
106.
Sachinkumar Dagurao Pangavhane Jan Houška Tomáš Wágner Martin Pavlišta Jan Janča Josef Havel 《Rapid communications in mass spectrometry : RCM》2010,24(1):95-102
Ternary chalcogenide As‐S‐Se glasses, important for optics, computers, material science and technological applications, are often made by pulsed laser deposition (PLD) technology but the plasma composition formed during the process is mostly unknown. Therefore, the formation of clusters in a plasma plume from different glasses was followed by laser desorption ionization (LDI) or laser ablation (LA) time‐of‐flight mass spectrometry (TOF MS) in positive and negative ion modes. The LA of glasses of different composition leads to the formation of a number of binary AspSq, AspSer and ternary AspSqSer singly charged clusters. Series of clusters with the ratio As:chalcogen = 3:3 (As3S, As3S2Se+, As3SSe), 3:4 (As3S, As3S3Se+, As3S2Se, As3SSe, As3Se), 3:1 (As3S+, As3Se+), and 3:2 (As3S, As3SSe+, As3Se), formed from both bulk and PLD‐deposited nano‐layer glass, were detected. The stoichiometry of the AspSqSer clusters was determined via isotopic envelope analysis and computer modeling. The structure of the clusters is discussed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
107.
Simultaneous determination of trans-resveratrol and sorbic acid in wine by capillary zone electrophoresis 总被引:2,自引:0,他引:2
A method for separation and determination of sorbic acid, a food and beverage preservative, and trans-resveratrol, a biomedically active substance, in wine by capillary zone electrophoresis is described. A solid-phase extraction step on C18-column prior to the electrophoretic separation providing lower detection limits was used for trans-resveratrol determination. For determination of sorbic acid direct analysis of wine (without a preconcentration step) was used. The method is rapid and sensitive and was applied to the analysis of wines from Alsace, France. 相似文献
108.
Pangavhane SD Hebedová L Alberti M Havel J 《Rapid communications in mass spectrometry : RCM》2011,25(7):917-924
Phosphorus nitride clusters generated during Laser Desorption Ionization (LDI) and Matrix-Assisted Laser Desorption Ionization (MALDI) of solid P(3) N(5) were analyzed via Time-of-Flight Mass Spectrometry (TOF MS). The LDI TOF mass spectra show the formation of series of clusters: P(m)N(n)(+) {(m=1; n=8-11), (m=4; n=3-4), (m=5; n=1-5), (m=6; n=1-3, 5-8), (m=2-7; n=1), (m=5-10; n=2), (m=4-6; n=3), (m=4,5; n=4), (m=5,6; n=5)}, and P(m)N(n)(-) (m=4,5; n=1). Using 3-hydroxypicolinic acid (HPA) as a matrix the P(m)N(n)(+) species (m=1-4, 6, 8) with a high nitrogen content (n=4, 5, 8, 10-12, 20) were identified. The formation of a N(6)(-) cluster was also detected using a C(60) matrix. Under various conditions singly charged P(m)(+) (m=2-7, 9, 13), P(m)(-) (m=3-11, 13, 15, 17), N(n)(+) (n=5, 9, 10, 12, 13), and N(n)(-) (n=6, 10-15) clusters were identified in the mass spectra. Such high nitrogen content clusters (up to N(15)(-)) generated by laser desorption from a solid material are described for the first time. The stoichiometry of the P(m)N(n) clusters was determined via isotopic envelope analysis and computer modelling. The composition of the clusters with respect to the crystalline structure of α-P(3)N(5) is discussed. 相似文献
109.
110.
Aequationes mathematicae - 相似文献