Dynamics of electron transfer reactions in ruthenium-based donor-chromophore-acceptor complexes involving phenothiazine-type donors |
Posted on:2002-07-28 | Degree:Ph.D | Type:Dissertation |
University:Colorado State University | Candidate:Limoges, Bradford Robert | Full Text:PDF |
GTID:1461390011496018 | Subject:Chemistry |
Abstract/Summary: | |
A series of electron donating groups were synthesized to study the effect of driving force on the electron transfer between the donor and a photoexcited trisbipyridineruthenium (II) chromophore. The driving force for the electron transfer reaction is directly related to the oxidation potential of the donor. The findings can be understood in terms of a combination of driving force and a π-π interaction between the donor and the chromophore.; The π-π interaction was investigated to determine its role in the electron transfer reaction. To this end, a series of bipyridine-like ligands were used to make chromophores that either favored or hindered the π-π interaction. The existence of the π-π interaction was shown by spectroscopy and NMR studies. The electron transfer rates for the ligand series reflect both the importance of the π-π interaction and driving force in these systems (ligand substitution affects the emission energy for a chromophore which in turn affects the driving force for the electron transfer reaction).; The effect of the π-π interaction on the electron transfers in donor-chromophore-acceptor complexes was investigated in bimolecular quenching experiments between donor and chromophore-acceptor complexes. The results can be understood in terms of a scheme where a ground state π-π interaction between the donor and the chromophore is the primary mode of electron transfer in these systems. The π-π interaction is also used to explain the high quantum efficiency to the charge-separated state, where both the donor and the acceptor have undergone electron transfers with the chromophore. |
Keywords/Search Tags: | Electron transfer, Chromophore, Driving force |
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