Mechanistic insight into organic and catalytic reactions by joint studies using mass spectrometry and NMR spectroscopy

Mass spectrometry, gas chromatography and deuterium NMR spectroscopy have been used to examine the products from the reactions of propene or cyclopentene with deuterium on calcium oxide. The information so gained on the number, location and grouping of the deuterium atoms in the products provides evidence about the nature and reactivity of the adsorbed intermediates involved in the catalytic reactions. The dominant mechanism of exchange, which occurs readily on calcium oxide even at 240 K with either propene or cyclopentene, is interconversion between adsorbed alkene and adsorbed π-allyl species. Catalysis of addition reactions also occurs, but at rates which are about 10 2 to 10 4 times slower than exchange. Different mechanisms of exchange mainly involving vinylic intermediates are found on γ-alumina.

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Mechanistic Insight into Nanoparticle Surface Adsorption by Solution NMR Spectroscopy in an Aqueous Gel

Angewandte Chemie International Edition ◽

10.1002/anie.201704471 ◽

2017 ◽

Vol 56 (33) ◽

pp. 9802-9806 ◽

Cited By ~ 15

Author(s):

Timothy K. Egner ◽

Pranjali Naik ◽

Nicholas C. Nelson ◽

Igor I. Slowing ◽

Vincenzo Venditti

Keyword(s):

Nmr Spectroscopy ◽

Surface Adsorption ◽

Solution Nmr ◽

Nanoparticle Surface ◽

Mechanistic Insight ◽

Solution Nmr Spectroscopy ◽

Insight Into

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Incremental iodination of the eight-vertex closo monocarborane anion [closo-1-CB7H8]–: Preparation and characterization of [closo-1-CB7H5-6,7,8-I3]– and [closo-1-CB7H2-2,3,4,6,7,8-I6]–, and the synthesis of the first eight-vertex C-methylated carborane anion [1-CH3-closo-1-CB7H4-6,7,8-I3]–

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2010068 ◽

2010 ◽

Vol 75 (9) ◽

pp. 931-947 ◽

Cited By ~ 1

Author(s):

Radim Dostál ◽

Michael G. S. Londesborough ◽

Magdalena Kvíčalová ◽

Jan Macháček ◽

Ivana Císařová ◽

...

Keyword(s):

Mass Spectrometry ◽

Nmr Spectroscopy ◽

Single Crystal ◽

Electrophilic Substitution ◽

X Ray Diffraction ◽

X Ray ◽

Molecular Behavior ◽

Elemental Iodine ◽

Insight Into

Iodination of [closo-1-CB7H8]– (anion 1) with elemental iodine under various controlled conditions yields a continuum from mono- to hexaiodinated derivatives including the previously unknown [closo-1-CB7H5-6,7,8-I3]– (anion 5) and [closo-1-CB7H2-2,3,4,6,7,8-I6]– (anion 8). These species, characterized by mass spectrometry and NMR spectroscopy, and, in the case of 8, by single-crystal X-ray diffraction, provide insight into the fluxional molecular behavior of anion 1 in solution. Investigation of direct electrophilic substitution on the carbon-vertex of anion 1 using standard conditions and reagents (deprotonation by BuLi followed by addition of electrophile) proved futile, but the same conditions when using the new triiodo-deravitive anion 5 resulted in the formation of the first eight-vertex C-methylated carborane anion [1-CH3-closo-1-CB7H4-6,7,8-I3]– (anion 9), in 60% yield.

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Mass Spectrometry and Imaging Analysis of Nanoparticle-Containing Vesicles Provide a Mechanistic Insight into Cellular Trafficking

ACS Nano ◽

10.1021/nn502754c ◽

2014 ◽

Vol 8 (10) ◽

pp. 10077-10088 ◽

Cited By ~ 58

Author(s):

Daniel Hofmann ◽

Stefan Tenzer ◽

Markus B. Bannwarth ◽

Claudia Messerschmidt ◽

Simone-Franziska Glaser ◽

...

Keyword(s):

Mass Spectrometry ◽

Cellular Trafficking ◽

Imaging Analysis ◽

Mechanistic Insight ◽

Insight Into

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Templating S100A9 amyloids on Aβ fibrillar surfaces revealed by charge detection mass spectrometry, microscopy, kinetic and microfluidic analyses

10.1101/2020.05.26.116400 ◽

2020 ◽

Author(s):

Jonathan Pansieri ◽

Igor A. Iashchishyn ◽

Hussein Fakhouri ◽

Lucija Ostojić ◽

Mantas Malisauskas ◽

...

Keyword(s):

Mass Spectrometry ◽

Disease Onset ◽

Secondary Nucleation ◽

Charge Detection Mass Spectrometry ◽

Charge Detection ◽

Mechanistic Insight ◽

New Directions ◽

Particle Level ◽

Biophysical Techniques ◽

Insight Into

The mechanism of amyloid co-aggregation and its nucleation process are not fully understood in spite of extensive studies. Deciphering the interactions between proinflammatory S100A9 protein and Aβ42 peptide in Alzheimer’s disease is fundamental since inflammation plays a central role in the disease onset. Here we use innovative charge detection mass spectrometry (CDMS) together with biophysical techniques to provide mechanistic insight into the co-aggregation process and differentiate amyloid complexes at a single particle level. Combination of mass and charge distributions of amyloids together with reconstruction of the differences between them and detailed microscopy reveals that co-aggregation involves templating of S100A9 fibrils on the surface of Aβ42 amyloids. Kinetic analysis further corroborates that the surfaces available for the Aβ42 secondary nucleation are diminished due to the coating by S100A9 amyloids, while the binding of S100A9 to Aβ42 fibrils is validated by a microfuidic assay. We demonstrate that synergy between CDMS, microscopy, kinetic and microfluidic analyses opens new directions in interdisciplinary research.

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Speciation and decomposition pathways of ruthenium catalysts used for selective C–H hydroxylation

Chemical Science ◽

10.1039/c4sc01050g ◽

2014 ◽

Vol 5 (8) ◽

pp. 3309-3314 ◽

Cited By ~ 16

Author(s):

Cornelia Flender ◽

Ashley M. Adams ◽

Jennifer L. Roizen ◽

Eric McNeill ◽

J. Du Bois ◽

...

Keyword(s):

Mass Spectrometry ◽

Metal Complex ◽

Desorption Electrospray Ionization ◽

Reactive Intermediates ◽

Ruthenium Catalysts ◽

Ionization Mass ◽

Mechanistic Insight ◽

Hydroxylation Reaction ◽

Desi Ms ◽

Insight Into

Mechanistic insight into the C–H hydroxylation reaction catalysed by [(Me3tacn)RuCl3] has been obtained using desorption electrospray ionization mass spectrometry (DESI-MS) to identify reactive intermediates and to determine the fate of the starting metal complex.

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