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Description
Mitochondria produce most of the ATP needed for the cell as an energy source. It is well known that cellular respiration results in oxidative damage to the cell due to the production of reactive oxygen species (ROS). Mitochondrial dysfunction is believed to contribute to a number of degenerative diseases; because

Mitochondria produce most of the ATP needed for the cell as an energy source. It is well known that cellular respiration results in oxidative damage to the cell due to the production of reactive oxygen species (ROS). Mitochondrial dysfunction is believed to contribute to a number of degenerative diseases; because of this the mitochondrial respiratory chain is considered as potential drug target. A few series of idebenone analogues with quinone, pyridinol and pyrimidinol redox cores have been synthesized and evaluated as antioxidants able to protect cellular integrity and, more specifically, mitochondrial function. The compounds exhibited a range of activities. The activities observed were used for the design of analogues with enhanced properties as antioxidants. Compounds were identified which provide better protection against oxidative stress than idebenone, and it is thought that they do so catalytically.
ContributorsArce Amezquita, Pablo M (Author) / Hecht, Sidney M. (Thesis advisor) / Moore, Ana (Committee member) / Rose, Seth (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Photochromic molecules, which photoisomerize between two chemically and optically distinct states, are well suited for electron and energy transfer to covalently attached chromophores. This dissertation aims to manipulate electron and energy transfer by photochromic control in a number of organic molecular systems. Herein the synthesis, characterization and function of these

Photochromic molecules, which photoisomerize between two chemically and optically distinct states, are well suited for electron and energy transfer to covalently attached chromophores. This dissertation aims to manipulate electron and energy transfer by photochromic control in a number of organic molecular systems. Herein the synthesis, characterization and function of these organic molecular systems will be described. Electron and energy transfer were quantified by the use of steady state absorbance and fluorescence, as well as time-resolved fluorescence and transient absorbance. A dithienylethene-porphrin-fullerene triad was synthesized to investigate photochromic control of photo-induced electron transfer. Control of two distinct electron transfer pathways was achieved by photochromic switching. A molecular dyad was synthesized, in which fluorescence was modulated by energy transfer by photoinduced isomerization. Also described is a triplet-triplet annihilation upconversion system that covalently attaches fluorophores to improve quantum yield. Overall these studies demonstrate complex molecular switching systems, which may lead to advancement in organic electronic applications and organic based artificial photosynthesis systems.
ContributorsCrisman, Jeffrey (Author) / Gust, John D (Thesis advisor) / Rose, Seth (Committee member) / Moore, Ana (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Sunlight, the most abundant source of energy available, is diffuse and intermittent; therefore it needs to be stored in chemicals bonds in order to be used any time. Photosynthesis converts sunlight into useful chemical energy that organisms can use for their functions. Artificial photosynthesis aims to use the essential chemistry

Sunlight, the most abundant source of energy available, is diffuse and intermittent; therefore it needs to be stored in chemicals bonds in order to be used any time. Photosynthesis converts sunlight into useful chemical energy that organisms can use for their functions. Artificial photosynthesis aims to use the essential chemistry of natural photosynthesis to harvest solar energy and convert it into fuels such as hydrogen gas. By splitting water, tandem photoelectrochemical solar cells (PESC) can produce hydrogen gas, which can be stored and used as fuel. Understanding the mechanisms of photosynthesis, such as photoinduced electron transfer, proton-coupled electron transfer (PCET) and energy transfer (singlet-singlet and triplet-triplet) can provide a detailed knowledge of those processes which can later be applied to the design of artificial photosynthetic systems. This dissertation has three main research projects. The first part focuses on design, synthesis and characterization of suitable photosensitizers for tandem cells. Different factors that can influence the performance of the photosensitizers in PESC and the attachment and use of a biomimetic electron relay to a water oxidation catalyst are explored. The second part studies PCET, using Nuclear Magnetic Resonance and computational chemistry to elucidate the structure and stability of tautomers that comprise biomimetic electron relays, focusing on the formation of intramolecular hydrogen bonds. The third part of this dissertation uses computational calculations to understand triplet-triplet energy transfer and the mechanism of quenching of the excited singlet state of phthalocyanines in antenna models by covalently attached carotenoids.
ContributorsTejeda Ferrari, Marely (Author) / Moore, Ana (Thesis advisor) / Mujica, Vladimiro (Thesis advisor) / Gust, John (Committee member) / Woodbury, Neal (Committee member) / Arizona State University (Publisher)
Created2016