Pogr The Final Oral Examination for the Degree of DOCTOR OF PHILOSOPHY (academic unit) Student name 2000 1997 UBC McGill University M.Sc. Hons. B.Sc. “title of dissertation” May 12th, 2008 2:00 pm David F. Strong building, room C114 Supervisory Committee: Dr. Peter C. Wan, Department of Chemistry, UVic (Supervisor) Dr. Alexander G. Briggs, Department of Chemistry, UVic Dr. Reginald H. Mitchell, Department of Chemistry, UVic Dr. Richard Keeler Department of Physics and Astronomy, UVic (Outside Member) External Examiner: Dr. Mark S. Workentin, Department of Chemistry, University of Western Ontario Chair of Oral Examination: TO BE COMPLETED BY FGS, Department of English, UVic Abstract The discovery and mechanistic investigation of a new class of photochemical reactions of benzophenones and related compounds is documented in this Thesis. Their photobehaviour in aqueous solvent media varied dramatically from their well-known behaviour in organic solvents and suggests unique and unprecedented mechanistic pathways. The aqueous photoredox chemistry of various substituted benzophenones was initially explored. Particular attention was paid to 3(hydroxymethyl)benzophenone, which upon photolysis in acidic aqueous media undergoes an intramolecular photoredox reaction to produce 3-formylbenzhydrol. Extensive investigation into the mechanistic behaviour of 3-(hydroxymethyl)benzophenone produced evidence of a unique solvent mediated, acid catalysed photoreaction. A mechanism has been proposed for the intramolecular photoredox reaction that proceeds via the protonated triplet state. This protonated triplet state subsequently promotes the deprotonation of the benzylic carbon before rearranging to form the redox product. The modification of the benzylic carbon with an alkyl group or with a phenyl group resulted in only slight changes in the photobehaviour. In both cases intramolecular photoredox reactions were observed although significantly more oligomeric side products were observed in some cases. To more fully elucidate photobehaviour and to test the generality of the photoredox reaction, a variety of different, structurally related hydroxyalkyl aromatic carbonyls were synthesized and studied. Alternative chromophores were explored using xanthone and fluorenone derivatives. Both derivative compounds underwent intramolecular photoredox reaction, supporting the assertion that the intramolecular photoredox reaction could be considered a general feature of aromatic carbonyls under aqueous conditions. However, significant differences in photoreactivity were also observed. It was found that 2(hydroxymethyl)xanthone exhibited sufficient photoactivity that the intramolecular photoredox reaction was observable even under neutral conditions whereas 2(hydroxymethyl)fluorenone was nearly photoinert. The last topic focuses on the extension of the electronic transmission from the carbonyl functional group to the benzylic alcohol by insertion of an additional phenyl group. The addition of the phenyl group also provided a bichromophoric molecule, rather than the monochromophoric substrates studied to this point. The substituent’s position played an important role in the photobehaviour, in that both of the meta- and orthosubstituted compounds underwent intramolecular photoredox reaction, while the para- substituted compound primarily exhibited photobehaviour indicative of hydrogen abstraction. Awards, Scholarships, Fellowships 2002 1993-1997 1993-1997 Dr. E. and Mrs. M. von Rudloff Scholarship J.W. McConnell Entrance Scholarship Canada Scholarship for Science and Engineering Presentations 1. Mitchell, D. and Wan, P. “Intramolecular Photoredox Chemistry induced by Anthraquinone through the Biphenyl Ring Systems” 85th Conference of the Canada Society for Chemistry, Vancouver, British Columbia, Canada. June 2002 (poster) 2. Mitchell, D; Lukeman, M. and Wan, P. “Intramolecular Photoredox Chemistry of Substituted Benzophenones – A New Class of Reaction for Aromatic Ketones.” 86th Conference of the Canada Society for Chemistry, Ottawa, Ontario, Canada., Aug. 2003.(oral) 3. Mitchell, D.; Basaric, N.; and Wan, P. “Intramolecular Photoredox Chemistry of Substituted Benzophenonesthe Effect of Phenyl Substituents.” 89th Conference of the Canada Society for Chemistry, Halifax, Nova Scotia, Canada. May. 2006.(oral) Publications 1. Storr, T.;* Mitchell, D.; Buglyó, P.; Thompson, K.H.; Yuen, V.; McNeill, J.H. and Orvig, C. *“VanadylThiazolidinedione Combination Agents for Diabetes Therapy.” Bioconjugate Chemistry 2003, 14 (1), 212 221. 2. Mitchell, D.*; Lukeman, M.; Lehnherr, D. and Wan, P. *“ Formal Intramolecular Photoredox Chemistry of Meta-Substituted Benzophenones” Organic Letters, 2005, 7(15), 3387 – 3389 3. Basaric, N.; Mitchell, D.; Wan, P. “Substituent effects in the intramolecular photoredox reactions of Benosphenones in aqueous solution.” Canadian Journal of Chemistry, 2007, 85, 561 - 571