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Application of Molecular Modeling Techniques Towards the Development of Molecular Baskets and HER Catalysts

Polen, Shane M, Polen
http://rave.ohiolink.edu/etdc/view?acc_num=osu1500564483601742

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Chemistry.
Acetylcholinesterase (AChE) is a serine hydrolase responsible for the hydrolysis of the neurotransmitter acetylcholine and is found throughout the body in synaptic clefts and in neuromuscular junctions. Acetylcholine (ACh) is released into the synaptic cleft following a neuronal impulse; ACh then binds to cholinergic receptors on postsynaptic cell membranes and triggers a response, such as a muscle contraction. In other words, ACh is the chemical that motor neurons of the nervous system release in order to activate muscles. Afterwards, ACh is released into the synaptic cleft where it is rapidly hydrolyzed by AChE. Organophosphorus (OP) compounds are substrate analogs to ACh and thus enter the active site and are attacked by Ser203 in a similar manner. This results in an inhibited phosphylated enzyme, and AChE is no longer able to bind and hydrolyze ACh. After inhibition, a process known as aging occurs through O-dealkylation of the OP-AChE adduct, which results in an anionic phosphylated serine residue that is resistant to nucleophilic attack. At this point, the enzyme is referred to as “aged” because it is resistant to reactivation. The result of inhibition and aging is the accumulation of ACh in neuromuscular junctions, which causes a cholinergic crisis, the overstimulation of nicotinic (nAChR) and muscarinic (mAChR) receptors. There are mulptiple strategies to combat OP poisioning; the first part of this dissertation explores the design of a series of bioscavengers that can be used to sequester the OP before inhibition of AChE occurs. The his dissertation focuses on the application of a wide variety of molecular modeling to better understand the non-covalent interactions between molecular baskets and their target guest molecules and to verify observed experimental properties of these systems. The second main focus of this thesis is the application of molecular modeling techniques to the development of molybdenum sulfide based hydrogen evolution reaction (HER) catalysts. In 2011 total worldwide hydrogen production exceeded 31 million metric tons; most of this hydrogen was used to manufacture ammonia via the Haber-Bosch process or in the petrochemical industry. Hydrogen is an ideal alternative fuel source due to its high energy density and carbon free emissions. The electrolysis of water to form H2 and O2 (water splitting) is an attractive alternative for fossil fuel reformation as the starting material (water) is recovered when hydrogen fuel is consumed and the input energy required to electrolyze the water can be provided by renewable sources. Water splitting can be divided into two half reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Both of these reactions require a catalyst to reduce the overpotential of the reaction, thereby increasing the energy efficiency. The best HER electrocatalyst to date is platinum, which has a near-zero overpotential. Given the cost and scarcity of platinum, the development of robust and sustainable alternative catalysts is critical to the advancement of hydrogen as a viable fuel source.
Christopher Hadad (Advisor)
Jovica Badjic (Committee Member)
Yiying Wu (Committee Member)
Charles Daniels (Committee Member)
438 p.
Chemistry
Chemistry, Molecular Modeling Techniques

Recommended Citations

Citations

  • Polen, Polen, S. M. (2017). Application of Molecular Modeling Techniques Towards the Development of Molecular Baskets and HER Catalysts [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500564483601742

    APA Style (7th edition)

  • Polen, Polen, Shane. Application of Molecular Modeling Techniques Towards the Development of Molecular Baskets and HER Catalysts . 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1500564483601742.

    MLA Style (8th edition)

  • Polen, Polen, Shane. "Application of Molecular Modeling Techniques Towards the Development of Molecular Baskets and HER Catalysts ." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500564483601742

    Chicago Manual of Style (17th edition)

osu1500564483601742
263
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This open access ETD is published by The Ohio State University and OhioLINK.