Boron-containing aromatic compounds: synthesis, characterization and reactivity

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dc.contributor.advisorPiers, Warren E.
dc.contributor.advisorKeay, Brian A.
dc.contributor.authorWood, Thomas Kuchurean
dc.date.accessioned2017-12-18T22:03:04Z
dc.date.available2017-12-18T22:03:04Z
dc.date.issued2009
dc.descriptionBibliography: p. 165-173en
dc.descriptionSome pages are in colour.en
dc.description.abstractBoron-containing derivatives of barrelene and benzobarrelene were generated in good to excellent yields by Diels-Alder reactions between Lewis base-stabilized borabenzene and strong dienophiles. The resultant Diels-Alder adducts were more stable when the Lewis base donor atom was nitrogen as opposed to phosphorus. All members of the family were found to be highly Lewis acidic, and the neutral donors which ligated the boron atom could not be removed/exchanged. Most compounds exhibited a high degree of thermal stability and underwent ill-defined decomposition only when heated to temperatures in excess of 200 °C. In selected cases the Diels-Alder reaction was found to be reversible and the free borabenzene, formed transiently through a retro-Diels-Alder reaction, could be trapped if a stronger dienophile was present in solution. When one of the barrelenes was treated with 3,6-di(2-pyridyl)-1,2,4,5-tetrazine, acetylene was removed to give the first 2,3-disubstituted borabenzene pyridine adduct. Additionally, syntheses were developed for boron-doped versions of the larger acenes: anthracene, naphthacene and pentacene. Boron-doped acenes, 9-boraanthracene, 5-boranaphthacene, and 6-borapentacene, were generated upon deprotonation of appropriately constructed precursors in which the boron atom was ligated by an Arduengo carbene (1,3-bis(2,4,6-trimethyl)imidazolidin-2-ylidene ). These molecules were more highly coloured than their corresponding all-carbon counterparts, an observable manifestation of their much smaller HOMO-LUMO gap. This decrease in HOMO-LUMO gap was found to be a result of an increase in the energy of the HOMO, and is attributable to the boron's presence in the acene's n system. Additionally, the smallest member of this family, 9-boraanthracene, was also found to react with strong dienophiles and 0 2 to form Diels-Alder adducts. During the course of this research, two stable spirocyclic boronium ions were also generated, both of which proved to be valuable starting materials for neutral boron-centred radicals.En
dc.format.extentxxii, 222 leaves : ill. ; 30 cm.en
dc.identifier.citationWood, T. K. (2009). Boron-containing aromatic compounds: synthesis, characterization and reactivity (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/3274en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/3274
dc.identifier.urihttp://hdl.handle.net/1880/104275
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.titleBoron-containing aromatic compounds: synthesis, characterization and reactivity
dc.typedoctoral thesis
thesis.degree.disciplineChemistry
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 1906 520502076
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleaseyen
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