Photophysics and photochemistry of pyridine-bridged chromophores
department or school: Science, Faculty of
department or school: Chemistry, Department of
data provider: DSpace
degree campus: UBCV
creator: Yunyaeva, Olga
issued: 2022-09-30T07:00:00Z
issued: 2021
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Organic π-conjugated materials are growing in popularity as they can be employed in flexible devices such as OLED displays, used in bioimaging, and for sensing applications. The incorporation of heteroatoms, in particular nitrogen, provides a simple synthetic handle that can be used to modify organic emitters through reactions such as protonation, oxidation, alkylation, and chelation, leading to a new class of molecules with different photophysical properties. This thesis explores a series of pyridine-containing luminophores arranged in donor-acceptor architectures and the changes in the photophysical properties when functionalized at the nitrogen center. First, a spectroscopic study examines the effect of substituent size at the nitrogen on the conformational and rotational properties of the molecule. Modification of the nitrogen by protonation, oxidation and alkylation are investigated and differences in photophysical properties are observed. Substitutions with groups larger than a hydrogen induce restricted rotation in specific molecules resulting in atropisomerism. NMR, UV-Vis, and emission spectroscopies are used to explain the impact of different substitutions on fluorescence quantum yield. Next, a new photoreaction is demonstrated in which a C–N bond is formed between pyridine and different polyaromatic hydrocarbons (PAHs). Protonation and chelation of the pyridine enables compounds to react under UV irradiation. The mechanism of this photoreaction is explored using kinetic experiments, revealing a photochemically driven single electron transfer (SET) reaction. The scope of this reaction is tested with different chromophores, electron-withdrawing/donating groups and under various reaction conditions. The formation of the C–N bond leads to planarization and rigidification of the photoproduct, leading to a redshift in emission wavelength and an increase in fluorescence quantum yield.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/79743
note: PHOTOPHYSICS AND PHOTOCHEMISTRY OF PYRIDINE-BRIDGED CHROMOPHORES by Olga Yunyaeva B.Sc., The University of Western Ontario, 2018 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Chemistry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) September 2021 © Olga Yunyaeva, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Photophysics and Photochemistry of Pyridine-Bridged Chromophores submitted by Olga Yunyaeva in partial fulfillment of the requirements for the degree of Master of Science in Chemistry Examining Committee: Michael Wolf, Professor, Department of Chemistry, UBC Supervisor Glenn Sammis, Professor, Department of Chemistry, UBC Supervisory Committee Member Derek Gates, Professor, Department of Chemistry, UBC Supervisory Committee Member Lawrence McIntosh, Professor Emeritus, Department of Chemistry and Department of Biochemistry and Molecular Biology/ The Michael Smith Laboratories, UBC Additional Examiner iii Abstract Organic π-conjugated materials are growing in popularity as they can be employed in flexible devices such as OLED displays, used in bioimaging, and for sensing applications. The incorporation of heteroatoms, in particular nitrogen, provides a simple synthetic handle that can be used to modify organic emitters through reactions such as protonation, oxidation, alkylation, and chelation, leading to a new class of molecules with different photophysical properties. This thesis explores a series of pyridine-containing luminophores arranged in donor-acceptor architectures and the changes in the photophysical properties when functionalized at the nitrogen center. First, a spectroscopic study examines the effect of substituent size at the nitrogen on the conformational and rotational properties of the molecule. Modification of the nitrogen …
has type: Thesis/Dissertation
date issued: 2021-11
is shown at: 10.14288/1.0402328
language: eng
degree discipline: Chemistry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Wolf, Michael O.
type: Text
identifier URI: http://hdl.handle.net/2429/79743