Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Chemistry

Supervisor

Blacquiere, Johanna M.

Abstract

This thesis attempts to use Ru and Pd complexes ligated with 1,5-R-3,7-Rʹ-1,5-diaza-3,7-diphosphacyclooctane (PR2NR’2) ligands for organic transformations. Herein, intermolecular hydroamination of terminal alkynes using [Ru(Cp/Cp*)(PR2NR’2)(MeCN]PF6 (Cp = cyclopentadienyl, Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl) was investigated but it resulted in the formation of two deactivation products. In contrast, intermolecular hydration was successful, and this is the first instance of intermolecular chemistry with Ru-PR2NR’2 complexes. Intermolecular hydroalkoxylation with 1-octyne and phenol was also successful, but an aryl alkyne substrate scope was unsuccessful. Linear alcohols resulted in the formation of an undesired acetal product, yet interesting selectivity for the Z product was observed with phenylacetylene and propanol as substrates. It was previously observed that Pd-PR2NR’2 complexes showed divergent selectivity for the linear or branched products dependent on the phosphorus R substituent in the Heck coupling of phenyltriflate and styrene. To understand the selectivity, reaction intermediates were synthesized, preliminary characterization was collected, and catalysis was performed.

Summary for Lay Audience

Catalysts are substances that help cause reactions to occur. They are important because they have the potential to provide a more environmentally friendly way to make desired chemical products, direct selectivity in product formation, and be easy to use. But in order to achieve these things and therefore have a good catalytic system, we need to understand how catalyst structures work. Ligands are molecules that are attached to the metal part of catalysts, and they influence how a catalyst performs. This work looks at a particular type of family of ligands, referred to as P2N2 ligands, that are attached to ruthenium and palladium metals. Attempts are made to use and understand how the ligand works in three different types of reactions. Two of the reactions aim at making compounds that contain oxygen and nitrogen atoms, which are valuable frameworks featured in drugs and natural products. The reaction to make nitrogen containing compounds was unsuccessful, yet the information gained indicates ways that the family of ligands could be altered to one day lead to success. In contrast, the reaction involving oxygen was successful and the success indicates this catalyst structure could be promising for similar reactions. The third reaction looked at the selective formation of two products and why one product was favoured over another, depending on which ligand was attached to the metal center. Overall, this work highlights the potential that this family of ligands could have of synthesizing compounds in a way that is low waste, green and selective.

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