{"title":"Magnetic susceptibility effect on the 19F chemical shift of p-fluoroacetophenone molecules adsorbed in FAU and MFI zeolites","authors":"A Simon, L Delmotte, J.M Chézeau","doi":"10.1016/S0927-6513(97)00043-6","DOIUrl":null,"url":null,"abstract":"<div><p>The aim of this study is to distinguish the effect on the chemical shift of the anisotropy of sample magnetism (shape, chemical composition, external magnetic field <em>B</em><sub>0</sub>) from the local effect (binding electron, neighbouring nuclei) for NMR experiments. We calculate the former for an angle <em>θ</em>=54°44″ (magic angle) between the <em>B</em><sub>0</sub> direction and the axis of the rotor. For a small adsorption rate of <em>p</em>-fluoroacetophenone on MFI and FAU-type zeolites, this effect on <sup>19</sup>F chemical shift is not negligible, and it depends on the zeolite nature and structure type. The <em>δ</em><sub>obs</sub> correction varies from +1.8<!--> <!-->ppm for MFI with Si/Al ≥35.5 to about +1.4<!--> <span>ppm for FAU zeolites with Si/Al=2.9 and 21.</span></p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 3","pages":"Pages 207-211"},"PeriodicalIF":0.0000,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00043-6","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microporous Materials","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0927651397000436","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
The aim of this study is to distinguish the effect on the chemical shift of the anisotropy of sample magnetism (shape, chemical composition, external magnetic field B0) from the local effect (binding electron, neighbouring nuclei) for NMR experiments. We calculate the former for an angle θ=54°44″ (magic angle) between the B0 direction and the axis of the rotor. For a small adsorption rate of p-fluoroacetophenone on MFI and FAU-type zeolites, this effect on 19F chemical shift is not negligible, and it depends on the zeolite nature and structure type. The δobs correction varies from +1.8 ppm for MFI with Si/Al ≥35.5 to about +1.4 ppm for FAU zeolites with Si/Al=2.9 and 21.
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