Charge transfer dynamics in bridged donor-acceptor molecular assemblies
Thesis (Ph.D.)--Memorial University of Newfoundland, 2011. Chemistry Includes bibliographical references. -- Error in pagination: no page 239 used. The metabolic processes inherent to life on earth are driven by chemical transformations that are too numerous to count. Important classes of reactions...
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2011
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Online Access: | http://collections.mun.ca/cdm/ref/collection/theses5/id/12225 |
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Memorial University of Newfoundland: Digital Archives Initiative (DAI) |
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English |
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Proton transfer reactions Electron donor-acceptor complexes Oxidation-reduction reaction |
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Proton transfer reactions Electron donor-acceptor complexes Oxidation-reduction reaction El-Dali, Abdelmeneim, 1971- Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
topic_facet |
Proton transfer reactions Electron donor-acceptor complexes Oxidation-reduction reaction |
description |
Thesis (Ph.D.)--Memorial University of Newfoundland, 2011. Chemistry Includes bibliographical references. -- Error in pagination: no page 239 used. The metabolic processes inherent to life on earth are driven by chemical transformations that are too numerous to count. Important classes of reactions involve the transfer of charge, i.e. electron transfer and proton transfer as well as group transfer reactions. The recent X-ray crystal structure reveled that proton coupled electron transfer reactivity plays crucial rule in the photosynthetic apparatus. The theory to describe proton coupled electron transfer is not as evolved to that which described electron transfer. There exist a number of unresolved issues. The primary goal of this work was to understand at a very fundamental level, the molecular properties that dictate chemical reactivity so as to quantify the important factors which influence the charge transfer excited-state dynamics. In this work, we have applied a variety of different techniques to study the properties and the mechanism of ground state and excited state intermolecular and intramolecular proton transfer and charge transfer in chromosphere assemblies. -- The bbim system was studied to outline fundamental investigation with respect to the excited state intramolecular proton transfer. The ground state potential energy surface was characterized by temperature dependent 1H NMR to establish the energetics of the enol / keto inter-conversion in the ground state. Analysis of the temperature dependent 1H NMR yielded ΔHǂ = 27 kJmol -1, ΔSǂ = -133 JK-1mol-1. Upon excitation, bbim is a dual emitter with high energy emission band at 427 nm and 550 nm respectively. The intensity of transitions was found to be solvent dependent. Addition of D2O resulted in dramatic changes in the intensity and energetics of emission spectrum envelope. The emission spectra were subjected to a Franck-Condon line shape analysis and provide structural and electronic of the excited states. -- The photophysical properties of bbim were dependent on the electrolyte. Dramatic changes in the absorption and emission spectra were observed with [NBu4]F and [NBu4]OH. Titration experiment with a number of [N(Bu)4]X, where X is fluoride (F¯), chloride (Cl¯), bromide (Br¯), iodide (l¯), acetate ( Ac¯), hydrogen sulphate (HSO4¯), hexafluorophosphate (PF6¯). The equilibrium constants were valuated using singular value decomposition, or global analysis. The analysis suggests a complex equilibrium consisting of eight distinct species in the ground stat. For the excited state bbim a similar analysis describe above yielded six step equilibra. The potential application of bbim as a anion sensor which can discriminate the anion however this compound are air sensitive when excited in present of air. -- A second distinct study was focused on the 3-aminocoumarin (3-AC). The emission spectral fitting results were consistent with a small change in the structural in the ground and excited state. This study was first to use emission spectral fitting as a tool to probe the excited state and was consistent with expectation of the energy gap law was obeyed. At the present time more experiments are required to understand the position of substituent and the nature of emitting state. The data suggests the intervention of a ICT and TICT state in excited state decay. DFT calculations were carried out to understand the electronic structure in the ground state. |
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Memorial University of Newfoundland. Dept. of Chemistry |
format |
Thesis |
author |
El-Dali, Abdelmeneim, 1971- |
author_facet |
El-Dali, Abdelmeneim, 1971- |
author_sort |
El-Dali, Abdelmeneim, 1971- |
title |
Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
title_short |
Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
title_full |
Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
title_fullStr |
Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
title_full_unstemmed |
Charge transfer dynamics in bridged donor-acceptor molecular assemblies |
title_sort |
charge transfer dynamics in bridged donor-acceptor molecular assemblies |
publishDate |
2011 |
url |
http://collections.mun.ca/cdm/ref/collection/theses5/id/12225 |
genre |
Newfoundland studies University of Newfoundland |
genre_facet |
Newfoundland studies University of Newfoundland |
op_source |
Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries |
op_relation |
Electronic Theses and Dissertations (15.12 MB) -- http://collections.mun.ca/PDFs/theses/El-Dali_Abdelmeneim.pdf http://collections.mun.ca/cdm/ref/collection/theses5/id/12225 |
op_rights |
The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. |
_version_ |
1766113365246083072 |
spelling |
ftmemorialunivdc:oai:collections.mun.ca:theses5/12225 2023-05-15T17:23:34+02:00 Charge transfer dynamics in bridged donor-acceptor molecular assemblies El-Dali, Abdelmeneim, 1971- Memorial University of Newfoundland. Dept. of Chemistry 2011 xxxv, 255 leaves : ill. (some col.) Image/jpeg; Application/pdf http://collections.mun.ca/cdm/ref/collection/theses5/id/12225 Eng eng Electronic Theses and Dissertations (15.12 MB) -- http://collections.mun.ca/PDFs/theses/El-Dali_Abdelmeneim.pdf http://collections.mun.ca/cdm/ref/collection/theses5/id/12225 The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Paper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries Proton transfer reactions Electron donor-acceptor complexes Oxidation-reduction reaction Text Electronic thesis or dissertation 2011 ftmemorialunivdc 2015-08-06T19:22:48Z Thesis (Ph.D.)--Memorial University of Newfoundland, 2011. Chemistry Includes bibliographical references. -- Error in pagination: no page 239 used. The metabolic processes inherent to life on earth are driven by chemical transformations that are too numerous to count. Important classes of reactions involve the transfer of charge, i.e. electron transfer and proton transfer as well as group transfer reactions. The recent X-ray crystal structure reveled that proton coupled electron transfer reactivity plays crucial rule in the photosynthetic apparatus. The theory to describe proton coupled electron transfer is not as evolved to that which described electron transfer. There exist a number of unresolved issues. The primary goal of this work was to understand at a very fundamental level, the molecular properties that dictate chemical reactivity so as to quantify the important factors which influence the charge transfer excited-state dynamics. In this work, we have applied a variety of different techniques to study the properties and the mechanism of ground state and excited state intermolecular and intramolecular proton transfer and charge transfer in chromosphere assemblies. -- The bbim system was studied to outline fundamental investigation with respect to the excited state intramolecular proton transfer. The ground state potential energy surface was characterized by temperature dependent 1H NMR to establish the energetics of the enol / keto inter-conversion in the ground state. Analysis of the temperature dependent 1H NMR yielded ΔHǂ = 27 kJmol -1, ΔSǂ = -133 JK-1mol-1. Upon excitation, bbim is a dual emitter with high energy emission band at 427 nm and 550 nm respectively. The intensity of transitions was found to be solvent dependent. Addition of D2O resulted in dramatic changes in the intensity and energetics of emission spectrum envelope. The emission spectra were subjected to a Franck-Condon line shape analysis and provide structural and electronic of the excited states. -- The photophysical properties of bbim were dependent on the electrolyte. Dramatic changes in the absorption and emission spectra were observed with [NBu4]F and [NBu4]OH. Titration experiment with a number of [N(Bu)4]X, where X is fluoride (F¯), chloride (Cl¯), bromide (Br¯), iodide (l¯), acetate ( Ac¯), hydrogen sulphate (HSO4¯), hexafluorophosphate (PF6¯). The equilibrium constants were valuated using singular value decomposition, or global analysis. The analysis suggests a complex equilibrium consisting of eight distinct species in the ground stat. For the excited state bbim a similar analysis describe above yielded six step equilibra. The potential application of bbim as a anion sensor which can discriminate the anion however this compound are air sensitive when excited in present of air. -- A second distinct study was focused on the 3-aminocoumarin (3-AC). The emission spectral fitting results were consistent with a small change in the structural in the ground and excited state. This study was first to use emission spectral fitting as a tool to probe the excited state and was consistent with expectation of the energy gap law was obeyed. At the present time more experiments are required to understand the position of substituent and the nature of emitting state. The data suggests the intervention of a ICT and TICT state in excited state decay. DFT calculations were carried out to understand the electronic structure in the ground state. Thesis Newfoundland studies University of Newfoundland Memorial University of Newfoundland: Digital Archives Initiative (DAI) |