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991.
Molecular Level Characterization of the Structure and Interactions in Peptide‐Functionalized Metal–Organic Frameworks 下载免费PDF全文
Dr. Tanya K. Todorova Dr. Xavier Rozanska Dr. Christel Gervais Dr. Alexandre Legrand Dr. Linh N. Ho Pierrick Berruyer Dr. Anne Lesage Prof. Lyndon Emsley Dr. David Farrusseng Dr. Jérôme Canivet Dr. Caroline Mellot‐Draznieks 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(46):16531-16538
We use density functional theory, newly parameterized molecular dynamics simulations, and last generation 15N dynamic nuclear polarization surface enhanced solid‐state NMR spectroscopy (DNP SENS) to understand graft–host interactions and effects imposed by the metal–organic framework (MOF) host on peptide conformations in a peptide‐functionalized MOF. Focusing on two grafts typified by MIL‐68‐proline ( ‐Pro ) and MIL‐68‐glycine‐proline ( ‐Gly‐Pro ), we identified the most likely peptide conformations adopted in the functionalized hybrid frameworks. We found that hydrogen bond interactions between the graft and the surface hydroxyl groups of the MOF are essential in determining the peptides conformation(s). DNP SENS methodology shows unprecedented signal enhancements when applied to these peptide‐functionalized MOFs. The calculated chemical shifts of selected MIL‐68‐NH‐ Pro and MIL‐68‐NH‐ Gly‐Pro conformations are in a good agreement with the experimentally obtained 15N NMR signals. The study shows that the conformations of peptides when grafted in a MOF host are unlikely to be freely distributed, and conformational selection is directed by strong host–guest interactions. 相似文献
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TiO2 nanotubes as recyclable catalyst for efficient photocatalytic degradation of indigo carmine dye
Leonardo L. Costa Alexandre G.S. Prado 《Journal of photochemistry and photobiology. A, Chemistry》2009,201(1):45-49
TiO2 nanotubes have been synthesized in a hydrothermal system. The nanotubes were characterized by scanning electronic microscopy (SEM), FT-Raman spectroscopy and surface charge density by surface area analyzer. These nanocatalysts were applied to photocatalyse indigo carmine dye degradation. Photodegradation ability of TiO2 nanotubes was compared to TiO2 anatase photoactivity. Indigo carmine dye was completely degraded at 60 and 110 min of reaction catalysed by TiO2 nanotubes and TiO2 anatase, respectively. TiO2 nanotubes presented high photodegradation activity at pH 2 and TiO2 anatase at pH 4. TiO2 nanotubes were easily recycled whereas the reuse of TiO2 anatase was not effective. Nanotubes maintained 90% of activity after 10 catalytic cycles and TiO2 anatase presented only 10% of its activity after 10 cycles. 相似文献
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Helio A. Martins‐Júnior Daniel T. Lebre Alexandre Y. Wang Maria A. F. Pires Oscar V. Bustillos 《Rapid communications in mass spectrometry : RCM》2009,23(7):1029-1034
A simple and specific method using reversed‐phase liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) was investigated, which allowed the determination of residues of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in soybean samples. An aqueous extraction with liquid‐liquid partition followed by protein precipitation was performed before the LC/MS/MS determination. The quantitation of glyphosate and AMPA was performed in positive and negative ESI mode, respectively, using the multiple reaction monitoring (MRM) mode with three transitions for each analyte to enhance the specificity of the method and avoid false positives. The methodology reported in this work is capable of detecting residues of glyphosate and AMPA in soybean samples with limits of quantification of 0.30 and 0.34 mg kg?1, respectively. This alternative method has throughput advantages such as simpler sample preparation and faster chromatographic analysis. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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