Chemical shift tensors of reactive intermediates on solid acids : a combination of NMR experiment and theory /
The primary focus of this research was to investigate ofilm Inc. reactive intermediates in solid acid media by both theoretical methods and solid state MAS NMR. A variety of chemical systems were considered. Among the acids were metal halide superacids, zeolite systems, frozen ileum, and boron trifl...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733038991&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The primary focus of this research was to investigate ofilm Inc. reactive intermediates in solid acid media by both theoretical methods and solid state MAS NMR. A variety of chemical systems were considered. Among the acids were metal halide superacids, zeolite systems, frozen ileum, and boron trifluoride. The chemical intermediates studied included acylium, benzenium, nitrilium, nitronium, and nitrosonium cations. Measurements were often performed at subambient temperatures, usually 77 K. Also, an investigation of proton chemical shifts of some classic hydrogen bonded molecules demonstrated the need for caution when ignoring treatment of electron correlation as is often done in the literature for such calculations. The theory was generally comprised of determining equilibrium structures and transition states, then calculating the propel-ties of those species and comparing to measured values. High levels of theory and use of medium-to-large basis sets are often required in the case of GIAO chemical shifts. Very good agreement with experimental chemical shift tensors was achieved in most cases. At the levels of theory used for the above cases, the theory failed for some extreme test cases, specifically [] and []. Higher levels of theory (CCSD and CCSD(T)) provided accurate results for these challenging cases. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xiv, 205 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 170-185). |