Revealing the Configuration and Conformation of Surface Organometallic Catalysts with DNP-Enhanced NMR

2021 ◽  
Author(s):  
Frédéric A. Perras ◽  
Alexander L. Paterson ◽  
Zoha H. Syed ◽  
A. Jeremy Kropf ◽  
David M. Kaphan ◽  
...  
Keyword(s):  
Organometallic Catalysts ◽  
Configuration And Conformation

PHOTOACTIVATION OF ORGANOMETALLIC CATALYSTS

1980 ◽  
Vol 333 (1 Transition Me) ◽  
pp. 188-208 ◽  
Author(s):  
Mark S. Wrighton ◽  
James L. Graff ◽  
Carol L. Reichel ◽  
Robert D. Sanner
Keyword(s):  
Organometallic Catalysts

scholarly journals Stereochemistry and biological activity of chlorinated lipids: a study of danicalipin A and selected diastereomers

2017 ◽  
Vol 8 (10) ◽  
pp. 6904-6910 ◽  
Author(s):  
J. Boshkow ◽  
S. Fischer ◽  
A. M. Bailey ◽  
S. Wolfrum ◽  
E. M. Carreira
Keyword(s):  
Biological Activity ◽  
Configuration And Conformation

Impact of configuration and conformation of selected (+)-danicalipin A diastereomers on biological activity.

scholarly journals Inside Cover: Organometallic Catalysts for Use in a Fuel Cell (ChemCatChem 6/2013)

ChemCatChem ◽  
2013 ◽  
Vol 5 (6) ◽  
pp. 1214-1214
Author(s):  
Takahiro Matsumoto ◽  
Kyoungmok Kim ◽  
Hidetaka Nakai ◽  
Takashi Hibino ◽  
Seiji Ogo
Keyword(s):  
Fuel Cell ◽  
Organometallic Catalysts

Configuration and conformation of lithiated imines by DNMR studies and ab initio calculations

1981 ◽  
Vol 206 (2) ◽  
pp. 131-138 ◽  
Author(s):  
R.R. Fraser ◽  
N. Chuaqui-Offermanns ◽  
K.N. Houk ◽  
N.G. Rondan
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Configuration And Conformation

scholarly journals On Stereocontrol in Organocatalytic α-Chlorinations of Aldehydes

2021 ◽  
Author(s):  
Sebastian Ponath ◽  
Chetan Joshi ◽  
Amy T. Merrill ◽  
Volker Schmidts ◽  
Kim Greis ◽  
...  
Keyword(s):  
Ion Mobility ◽  
Resting State ◽  
Comprehensive Analysis ◽  
Ion Mobility Mass Spectrometry ◽  
Concentration Profiles ◽  
Nmr Studies ◽  
Isotope Studies ◽  
Configuration And Conformation

A comprehensive analysis of the organocatalytic α‐chlorination of aldehydes with N‐chloroimides and differ‐ ent catalysts is presented. For this reaction, alternate mechanisms were proposed that differ in the role of resting state intermediates and the rationalization of the observed enantioselectivity. This manuscript aims at resolving these funda‐ mental questions on the basis of rigorous structural characterization of intermediates (configuration and conformation), NMR studies, ion mobility‐mass spectrometry, concentration profiles, isotope studies, and DFT calculations. <br>

scholarly journals Computational Investigation of the Role of Active Site Heterogeneity for a Supported Organovanadium(III) Hydrogenation Catalyst

2021 ◽  
Author(s):  
Prajay Patel ◽  
Robert Wells ◽  
David Kaphan ◽  
Massimiliano Delferro ◽  
Rex T. Skodje ◽  
...  
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Density Functional ◽  
Computational Models ◽  
Surface Heterogeneity ◽  
Reaction Pathways ◽  
Spectroscopic Techniques ◽  
Organometallic Catalysts ◽  
Heterolytic Cleavage ◽  
Styrene Hydrogenation

<div> <div> <p></p><p><a>A crucial consideration for supported heterogeneous catalysts is the non-uniformity of the active sites, particularly for Supported Organometallic Catalysts (SOMCs). Standard spectroscopic techniques, such as X-ray absorption spectroscopy (XAS), reflect the nature of the most populated sites, which are often intrinsically structurally distinct from the most catalytically active sites. With computational models, often only a few representative structures are used to depict catalytic active sites on a surface, even though there are numerous observable factors of surface heterogeneity that contribute to the kinetically favorable active species. A previously reported study on the mechanism of a surface organovanadium(III) catalyst [(SiO)V<sup>III</sup>(Mes)(THF)] for styrene hydrogenation yielded two possible mechanisms: heterolytic cleavage and redox cycling. These two mechanistic scenarios are challenging to differentiate experimentally based on the kinetic readouts of the catalyst are identical. To showcase the importance of modeling surface heterogeneity and its effect on catalytic activity, density functional theory (DFT) computational models of a series of potential active sites of [(SiO)V<sup>III</sup>(Mes)(THF)] for the reaction pathways are applied in combination with kinetic Monte Carlo (kMC) simulations. Computed results were t then compared to the previously reported experimental kinetic study</a><a>.: 1) DFT free energy reaction pathways indicated the likely active site and pathway for styrene hydrogenation; a heterolytic cleavage pathway requiring a bare tripodal vanadium site. 2) From the kMC simulations, a mixture of the different bond lengths from the support oxygen to the metal center was required to qualitatively describe the experimentally observed kinetic aspects of a supported organovanadium(III) catalyst for olefin hydrogenation. </a>This work underscores the importance of modeling surface heterogeneity in computational catalysis.</p><p></p></div></div>

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