Synthetic and theoretical investigations of benzo -13 -p -tolyl phenalene.
Item
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Title
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Synthetic and theoretical investigations of benzo -13 -p -tolyl phenalene.
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Identifier
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AAI3103187
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identifier
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3103187
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Creator
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Zivkovic, Jelena T.
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Contributor
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Mentor: Klaus G. Grohmann
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Date
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2003
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Organic
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Abstract
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13-methylphenalene, a long sought after molecule, has been a synthetic objective in many research groups because of its suitability for the study of effects associated with antiaromatic, [4n] annulenes. This [12] annulene would have a rigid, nearly planar structure. Its high symmetry is predicted to minimize the pseudo Jahn-Taller effect, allowing the maximum paratropicity. The internal methyl group serves as a very sensitive NMR probe for the investigation of expected ring current effects. Previous experimental results in our group suggest the weakness of the methyl-central carbon bond: the attempts to introduce the last double bond into the system always led to the loss of the methyl group.;Based on the fact that the fusion of benzene rings onto annulene perimeter stabilizes the molecule, while lowering the paratropicity, the synthesis of Benzo-13-methylphenalene has been attempted, but the same facile methyl loss has been observed.;In order to strengthen the central carbon-carbon bond, changing the substituent from an alkyl (sp3) group to an aryl (sp2) group has been investigated. This investigation is comprised of two parts: (1) Theoretical study of the effects of benzannulation and substituent at the central position on bond dissociation energies (BDE's). Furthermore, two processes, namely the 1,5 shift and dissociation of the substituent group, are investigated as well. (2) The investigation of the very flexible synthetic methodology based on the intramolecular Diels-Alder reaction (IMDA) for the synthesis of a variety of benzo-13-substitutedphenalenes, including our synthetic target---Benzo-13-p-tolylphenalene, a molecule that, we believe, offers a perfect balance between paratropicity and isolabilty.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
