Ligand Design for Energy Conversion and Storage Applications
Date
2019-12-17
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Abstract
The contents of this thesis are divided into two topics that fall under the umbrella of energy conversion and storage. The first section focuses on tuning the standard reduction potential of the Fe3+/2+ redox couple with the aid of nitrogen-based ligands, in pursuit of an all-iron, water-based redox-flow battery. Also included is the synthesis and characterization of iron coordination complexes with redox-active ligands featuring quinone/hydroquinone functional groups. This study aims to exploit the potential of this system incorporating Fe3+/2+ and a redox non-innocent ligand for application in single-component redox-flow batteries. The second portion of the thesis targets homogeneous single-site catalysts for the electrochemical reduction of CO2. The ability of nickel and iron complexes incorporating a redox non-innocent bis(triazapentadienyl) ligand to promote this transformation was investigated. The nickel complex was identified as more promising and infrared spectroelectrochemistry was used to determine the fate of the metal during controlled potential electrolysis, as well as to identify the extent to which a large excess of ligand-based redox behavior impacts electrocatalytic CO2 reduction. The synthesis and characterization of other ligand scaffolds based on tetradentate bis(carbene) macrocycles and porphyrinoids is discussed, with alterations to the parent framework aimed at increasing solubility and stability during metal complexation. Also reported are efforts tailored towards the synthesis of ligands based on a bipyridine central donor with flanking phosphine chalcogenides. The phosphine oxide generated iron, nickel and rhenium complexes while the phosphine sulfide analog proved to be a surprisingly incompetent ligand.
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Keywords
Energy, Redox Flow Batteries, Batteries, Carbon Dioxide, Electrochemistry, Organometallics
Citation
Heidebrecht, J. (2019). Ligand Design for Energy Conversion and Storage Applications (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.