ChemInform Abstract: Residual Dipolar Coupling Effects in Solid State MAS NMR. Investigation of Proton Transfer Processes in Solids

ChemInform ◽  
2010 ◽  
Vol 32 (27) ◽  
pp. no-no
Author(s):  
Sergio H. Alarcon ◽  
Alejandro C. Olivieri
2021 ◽  
Vol 125 (8) ◽  
pp. 4869-4877
Author(s):  
Christian Schroeder ◽  
Stacey I. Zones ◽  
Christian Mück-Lichtenfeld ◽  
Michael Ryan Hansen ◽  
Hubert Koller

1988 ◽  
Vol 26 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Alejandro C. Olivieri ◽  
Lucio Frydman ◽  
Mariano Grasselli ◽  
Luis E. Diaz

2006 ◽  
Vol 84 (2) ◽  
pp. 345-355 ◽  
Author(s):  
Colin A Fyfe ◽  
Darren H Brouwer

The location of naphthalene in the zeolite ZSM-5 has been determined from solid-state 1H/29Si cross-polarization (CP) magic-angle-spinning (MAS) NMR data alone. With the peaks in the 29Si spectrum assigned to the inequivalent Si sites in the zeolite from a two-dimensional INADEQUATE spectrum, the rates of cross polarization between the 1H nuclei of the guest sorbate molecules and the 29Si nuclei of the zeolite framework were used to determine the location of the naphthalene molecules by exploiting the proportional relationship between cross-polarization rate constants and 1H/29Si dipolar coupling second moments. The NMR structure determination was carried out on three different selectively deuterium-labeled naphthalene molecules (naphthalene-d0, α-naphthalene-d4, and β-naphthalene-d4). The average of the molecule locations in agreement with all three sets of NMR data was found to be in excellent agreement with an existing single crystal XRD structure of the naphthalene–ZSM-5 complex.Key words: solid-state NMR, cross polarization, zeolites, host–guest complexes, structure determination.


2019 ◽  
Author(s):  
Przemyslaw Rzepka ◽  
Zoltán Bacsik ◽  
Andrew J. Pell ◽  
Niklas Hedin ◽  
Aleksander Jaworski

Formation of CO<sub>3</sub><sup>2-</sup> and HCO<sub>3</sub><sup>-</sup> species without participation of the framework oxygen atoms upon chemisorption of CO<sub>2</sub> in zeolite |Na<sub>12</sub>|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H<sub>2</sub>O or acid groups. A combined study by solid-state <sup>13</sup>C MAS NMR, quantum chemical calculations, and <i>in situ</i> IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO<sub>3</sub><sup>-</sup>. However, at a low surface coverage of physisorbed and acidic CO<sub>2</sub>, a significant fraction of the HCO<sub>3</sub><sup>-</sup> was deprotonated and transformed into CO<sub>3</sub><sup>2-</sup>. We expect that similar chemisorption of CO<sub>2</sub> would occur for low-silica zeolites and other basic silicates of interest for the capture of CO<sub>2</sub> from gas mixtures.


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