Formation, mobilité et réactivité d'espèces paramagnétiques adsorbées sur zéolithes H—Y irradiées. Une étude par résonance paramagnétique électronique

1976 ◽  
Vol 54 (11) ◽  
pp. 1678-1686 ◽  
Author(s):  
Jacques C. Vedrine ◽  
Jean Massardier ◽  
Antoine Abou-Kaïs
Keyword(s):  
Molecular Oxygen ◽  
Spin Density ◽  
Adsorbed Species ◽  
Y Zeolites ◽  
Γ Radiation ◽  
Adsorption Sites ◽  
Unpaired Spin ◽  
Original Approach ◽  
Adsorptive Properties ◽  
Monolayer Coverage

Use of γ radiation as an ionizing source has been successfully applied to an epr study of adsorption sites and of adsorbed species in the case of H—Y zeolites. Adsorption sites have appeared to be mainly oxygen nuclei from the lattice. It has been observed that molecular hydrogen neutralizes paramagnetic sites while molecular oxygen gives rise to O2−-type radicals which have nearly equal unpaired spin density on the two nuclei (43 and 57%). Carbon monoxide gives rise to a species assigned to C+O which reacts very easily at 77 K with molecular oxygen to yield an O2−-type species for which the spin density distribution is not equivalent on the two oxygen nuclei [Formula: see text] The nature and the mobility of OH• and NH2• radicals have been studied in detail. They arise from the ionization of physisorbed H2O and NH3, the better yield being obtained at a monolayer coverage. This study leads to an original approach to the study of the adsorptive properties of zeolites.

Unpaired Spin Density in OrderedFe3Al

1961 ◽  
Vol 123 (4) ◽  
pp. 1163-1171 ◽  
Author(s):  
S. J. Pickart ◽  
R. Nathans
Keyword(s):  
Spin Density ◽  
Unpaired Spin Density ◽  
Unpaired Spin

scholarly journals Functionalization of sewage sludge char by partial oxidation with molecular oxygen to enhance its adsorptive properties

2020 ◽  
pp. 125201
Author(s):  
María Atienza-Martínez ◽  
Nurull Nadia Binti Suraini ◽  
Javier Ábrego ◽  
Isabel Fonts ◽  
Luisa Lázaro ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Molecular Oxygen ◽  
Partial Oxidation ◽  
Oxidation With Molecular Oxygen ◽  
Sewage Sludge Char ◽  
Adsorptive Properties

Controlling Electron Transfer Dynamics in Donor−Bridge−Acceptor Molecules by Increasing Unpaired Spin Density on the Bridge†

2007 ◽  
Vol 111 (24) ◽  
pp. 6728-6737 ◽  
Author(s):  
Erin T. Chernick ◽  
Qixi Mi ◽  
Amy M. Vega ◽  
Jenny V. Lockard ◽  
Mark A. Ratner ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Density ◽  
Unpaired Spin Density ◽  
Unpaired Spin ◽  
Acceptor Molecules

Organophosphazenes. 25. The synthesis and electrochemistry of the dicobalt hexacarbonyl complexes of phenylethynylcyclophosphazenes

2002 ◽  
Vol 80 (11) ◽  
pp. 1393-1397 ◽  
Author(s):  
Maneesh Bahadur ◽  
Christopher W Allen ◽  
William E Geiger ◽  
Adam Bridges
Keyword(s):  
Spin Density ◽  
Nmr Spectra ◽  
Esr Spectra ◽  
Radical Anions ◽  
Electrochemical Studies ◽  
Unpaired Spin Density ◽  
Unpaired Spin ◽  
Electron Reduction ◽  
Dicobalt Hexacarbonyl

The syntheses of the dicobalt hexacarbonyl complexes, N3P3F6-n(C[Formula: see text]CPhCo2(CO)6)n (n = 1 (3), n = 2 (4)), is reported. The introduction of the organometallic fragment allows for simplification of the NMR spectra and separation of the isomers of the disubstituted (4) derivatives. Electrochemical studies show that 3 undergoes a reversible one-electron reduction. At 233 K, the geminal isomer of 4 undergoes two separate reversible one-electron reductions. The ESR spectra of the radical anions of 3 and 4 have been obtained and show the absence of delocalization of unpaired spin density from the organometallic cluster to the phosphazene.Key words: cyclophosphazenes, cobalt–alkyne clusters, electrochemistry, ESR.

scholarly journals Imido Cobalt Complexes with Imidyl Character

2021 ◽  
Author(s):  
alexander Reckziegel ◽  
Manjinder Kour ◽  
Beatrice Battistella ◽  
Stefan Mebs ◽  
Katrin Beuthert ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
High Spin ◽  
Bond Activation ◽  
High Spin State ◽  
Cobalt Complexes ◽  
Spectroscopic Methods ◽  
Computational Studies ◽  
Ancillary Ligand ◽  
Unpaired Spin

We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L<sub>2</sub>)<sup>–</sup>, (L = N(Dipp)SiMe<sub>3</sub>), Dipp = 2,6-diisopropylphenyl) bearing very long Co–NAryl bonds of around 1.75 Å. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from C–H bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me<sub>3</sub>Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular C–H bond activation.<br>

scholarly journals Studi investigasi adsorpsi oksigen pada permukaan ZnO[111]

2020 ◽  
Vol 4 (1) ◽  
pp. 21
Author(s):  
Listra Yehezkiel Ginting ◽  
Andam Deatama Refino ◽  
Lukman Nulhakim
Keyword(s):  
Molecular Oxygen ◽  
Energy Surface ◽  
Functional Materials ◽  
Oxygen Adsorption ◽  
Interesting Case ◽  
Adsorption Sites ◽  
Surface Survey ◽  
Translational Degree ◽  
Zno Crystal ◽  
Sample Case

The growth of ZnO is an interesting case in the study of functional materials. Adsorption of molecular oxygen onto the surface of Zn-terminated ZnO can be used as a sample case of ZnO crystal growth with its precursors. In this study, we want to see the tendency of molecular oxygen adsorption: whether it is adsorbed as a whole molecule or it is dissociated into the two constituting oxygen atoms before being adsorbed on oxygen adsorption sites for the growth of the crystal. Potential energy surface survey has been carried out on the three configuration of molecular oxygen based on their translational degree of freedom. The configuration of the oxygen molecule with O=O bond axis being normal to the surface tends to be adsorbed wholly as molecule with adsorption energy of 4.11 eV, while the configuration of bond perpendicular to the surface have the tendency to dissociate into individual atoms.

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