Oxygen activation and CO oxidation over size-selected Ptn/alumina/Re(0001) model catalysts: correlations with valence electronic structure, physical structure, and binding sites

2014 ◽  
Vol 16 (48) ◽  
pp. 26443-26457 ◽  
Author(s):  
F. Sloan Roberts ◽  
Matthew D. Kane ◽  
Eric T. Baxter ◽  
Scott L. Anderson
Keyword(s):  
Electronic Structure ◽  
Co Oxidation ◽  
Binding Sites ◽  
Oxygen Activation ◽  
Physical Structure ◽  
Model Catalysts ◽  
Valence Electronic Structure

Redox Potential - (Electronic) Structure Relationships in 18- and 17-Electron Mononitrile (or Monocarbonyl) Diphosphine Complexes of Re and Fe

2001 ◽  
Vol 66 (1) ◽  
pp. 139-154 ◽  
Author(s):  
M. Fátima C. Guedes Da Silva ◽  
Luísa M. D. R. S. Martins ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Cyclic Voltammetry ◽  
Electronic Structure ◽  
Binding Sites ◽  
Closed Shell ◽  
Carbonyl Complexes ◽  
Metal Centre ◽  
Pt Electrode ◽  
Metal Site ◽  
Oxidation Potentials ◽  
First Time

The organonitrile or carbonyl complexes cis-[ReCl(RCN)(dppe)2] (1) (R = 4-Et2NC6H4 (1a), 4-MeOC6H4 (1b), 4-MeC6H4 (1c), C6H5 (1d), 4-FC6H4 (1e), 4-ClC6H4 (1f), 4-O2NC6H4 (1g), 4-ClC6H4CH2 (1h), t-Bu (1i); dppe = Ph2PCH2CH2PPh2), or cis-[ReCl(CO)(dppe)2] (2), as well as trans-[FeBr(RCN)(depe)2]BF4 (3) (R = 4-MeOC6H4 (3a), 4-MeC6H4 (3b), C6H5 (3c), 4-FC6H4 (3d), 4-O2NC6H4 (3e), Me (3f), Et (3g), 4-MeOC6H4CH2 (3h); depe = Et2PCH2CH2PEt2), novel trans-[FeBr(CO)(depe)2]BF4 (4) and trans-[FeBr2(depe)2] (5) undergo, as revealed by cyclic voltammetry at a Pt-electrode and in aprotic non-aqueous medium, two consecutive reversible or partly reversible one-electron oxidations assigned as ReI → ReII → ReIII or FeII → FeIII → FeIV. The corresponding values of the oxidation potentials IE1/2ox and IIE1/2ox (waves I and II, respectively) correlate with the Pickett's and Lever's electrochemical ligand and metal site parameters. This allows to estimate these parameters for the various nitrile ligands, depe and binding sites (for the first time for a FeIII/IV couple). The electrochemical ligand parameter show dependence on the "electron-richness" of the metal centre. The values of IE1/2ox for the ReI complexes provide some supporting for a curved overall relationship with the sum of Lever's electrochemical ligand parameter. The Pickett parametrization for closed-shell complexes is extended now also to 17-electron complexes, i.e. with the 15-electron ReII and FeIII centres in cis-{[ReCl(dppe)2]}+ and trans-{FeBr(depe)2}2+, respectively.

CO Oxidation and Site Speciation for Alloyed Palladium–Platinum Model Catalysts Studied by in Situ FTIR Spectroscopy

2017 ◽  
Vol 121 (47) ◽  
pp. 26321-26329 ◽  
Author(s):  
Natalia M. Martin ◽  
Magnus Skoglundh ◽  
Gudmund Smedler ◽  
Agnes Raj ◽  
David Thompsett ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Ftir Spectroscopy ◽  
Model Catalysts ◽  
In Situ Ftir ◽  
In Situ Ftir Spectroscopy ◽  
Palladium Platinum

scholarly journals Chromatin extrusion explains key features of loop and domain formation in wild-type and engineered genomes

2015 ◽  
Vol 112 (47) ◽  
pp. E6456-E6465 ◽  
Author(s):  
Adrian L. Sanborn ◽  
Suhas S. P. Rao ◽  
Su-Chen Huang ◽  
Neva C. Durand ◽  
Miriam H. Huntley ◽  
...  
Keyword(s):  
Genome Editing ◽  
Binding Sites ◽  
Physical Structure ◽  
Ctcf Binding ◽  
Binding Motifs ◽  
Physical Simulations ◽  
Chromatin Folding ◽  
Mammalian Genomes ◽  
Single Base Pair ◽  
Fractal Globule

We recently used in situ Hi-C to create kilobase-resolution 3D maps of mammalian genomes. Here, we combine these maps with new Hi-C, microscopy, and genome-editing experiments to study the physical structure of chromatin fibers, domains, and loops. We find that the observed contact domains are inconsistent with the equilibrium state for an ordinary condensed polymer. Combining Hi-C data and novel mathematical theorems, we show that contact domains are also not consistent with a fractal globule. Instead, we use physical simulations to study two models of genome folding. In one, intermonomer attraction during polymer condensation leads to formation of an anisotropic “tension globule.” In the other, CCCTC-binding factor (CTCF) and cohesin act together to extrude unknotted loops during interphase. Both models are consistent with the observed contact domains and with the observation that contact domains tend to form inside loops. However, the extrusion model explains a far wider array of observations, such as why loops tend not to overlap and why the CTCF-binding motifs at pairs of loop anchors lie in the convergent orientation. Finally, we perform 13 genome-editing experiments examining the effect of altering CTCF-binding sites on chromatin folding. The convergent rule correctly predicts the affected loops in every case. Moreover, the extrusion model accurately predicts in silico the 3D maps resulting from each experiment using only the location of CTCF-binding sites in the WT. Thus, we show that it is possible to disrupt, restore, and move loops and domains using targeted mutations as small as a single base pair.

scholarly journals Direct observation of the site-specific valence electronic structure at SiO2/Si(111) interface

2006 ◽  
Vol 4 ◽  
pp. 280-284 ◽  
Author(s):  
Y. Yamashita ◽  
S. Yamamoto ◽  
K. Mukai ◽  
J. Yoshinobu ◽  
Y. Harada ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Direct Observation ◽  
Site Specific ◽  
Valence Electronic Structure

scholarly journals Valence electronic structure of [EMIM][B(CN)4]: ion-pair vs. bulk description

RSC Advances ◽  
2019 ◽  
Vol 9 (57) ◽  
pp. 33140-33146 ◽  
Author(s):  
I. Kuusik ◽  
M. Berholts ◽  
J. Kruusma ◽  
A. Tõnisoo ◽  
E. Lust ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Electronic Structure ◽  
Ab Initio ◽  
Photoelectron Spectrum ◽  
Ion Pair ◽  
Calculation Methods ◽  
Valence Electronic Structure

The ultraviolet photoelectron spectrum of the [EMIM][B(CN)4] ionic liquid was recorded and simulated using different ab initio ion-pair and bulk calculation methods.

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