| dc.contributor.author | Lee, Felix S. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:53Z | |
| dc.date.available | 2004 | |
| dc.date.issued | 2004 | en_US |
| dc.identifier.other | AAINQ94054 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/54669 | |
| dc.description | In enzymatically catalyzed reactions, the stabilization of reactive intermediates via amino-acid residues in the active site forms the basis of enzyme catalysis. It is essential then, that we understand the behaviour of enzyme-bound reactive intermediates to thoroughly understand biological catalysis. However, a major obstacle in the study of the behaviour of carbocations in active sites has been the lack of a method for their biocompatible, in situ generation. | en_US |
| dc.description | This thesis therefore investigates methods that could be used to "deliver" reactive intermediates from a organic, precursor substrate to hydrophobic sites, such as an enzyme active site. Specifically, using nanosecond laser-flash photolysis, tris(4,4'-disubstituted-2,2' -bipyridine)ruthenium photosensitizer complexes were used to oxidize substrates to their radical cations, the fragmentation reactions of which can generate carbocations. Initially, the intermolecular oxidation of a series of organic substrates by various ruthenium complexes in their Ru(II)* and Ru(III) states were studied. The rate constants for oxidation were dependent on both the electron-withdrawing properties of the ligand substituents and the substrate oxidation potentials. These results show that ruthenium complexes are useful for selective substrate oxidation in that their electrochemical properties can be fine-tuned by simple modification of the ligand. | en_US |
| dc.description | The intramolecular oxidation of an aromatic amine linked to the photosensitizers was also investigated to probe the dual-mechanism nature of oxidation. Herein, the substrate was oxidized by Ru(II)* and Ru(III) states, concomitant with the generation of Ru(I) and Ru(II), respectively. An unconventional use of an electron acceptor for the trapping of Ru(I) is also reported. | en_US |
| dc.description | Finally, the study culminates in the intramolecular oxidation of a hydrophobic, diphenylalkane substrate that, when oxidized to its radical cation, undergoes fragmentation to generate reactive carbocations. This method could possibly be used to "deliver" carbocations to hydrophobic sites. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 2004. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Biochemistry. | en_US |
| dc.title | Generation of radical cations and carbocations by tris(bipyridyl)ruthenium photosensitization. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
