Date of Award
Summer 2025
Document Type
Open Access Dissertation
Department
Chemistry and Biochemistry
First Advisor
Sheryl Wiskur
Abstract
Efficient organic synthesis often relies on improving catalyst designs and investigating reaction mechanisms to accomplish feats such as high stereoselectivity, low catalyst loadings, and performing sustainable chemistry. Within the field of organocatalysis, intermolecular interactions between a catalyst and a substrate are a large contributing factor to the control of a reaction, including rate and selectivity. Investigating mechanisms can provide information on the type of intermolecular interactions occurring in the reaction, aiding future reaction and catalyst development. This dissertation will explore two recent projects and how probing intermolecular interactions through simple modifications provides information useful for new catalyst designs and properties.
Isothiourea-based catalysts are common nucleophilic catalysts and have been used in the field of asymmetric silylation and acylation reactions. In this work, isothiourea-based catalysts were investigated to understand how favorable non-covalent interactions can lead to enantioselectivity in a model silylation reaction. Multiparameter Swain Lupton fits using Linear Free Energy Relationships (LFER) were devised to measure how changes in catalyst structure affect the intermolecular interactions that ultimately control selectivity.
Secondly, silicon phthalocyanines (SiPc) have been previously explored as redox-active photocatalysts and it was determined that alterations of the axial ligands led to differences in photoredox properties. This seminar will cover the development of multiple derivatives of these SiPcs, that vary at the axial position, and ultimately the photophysical and electrochemical properties of these novel silicon phthalocyanine derivatives. The structure of the axial ligands will be related to excited state photoredox potentials, Stern Volmer fluorescence quenching constants, and photoreactions using the ability of SiPcs to do electron and energy transfer. Lastly, Sterimol parameters were obtained to quantitatively correlate axial substituent structure to experimental photoredox results.
Rights
© 2025, Christian J Harrison
Recommended Citation
Harrison, C. J.(2025). Structure-Activity Relationships of Isothiourea and Silicon Phthalocyanine Catalysts. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8393