Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Chemistry

Supervisor

Blacquiere, Johanna M.

Abstract

Structurally responsive ligands (SRLs) are dynamic ligands that can alter coordination mode with a metal centre, to stimulate fundamental organometallic reactions in several catalytic cycles. These dynamic ligand coordination changes can also enable access to unique reaction mechanisms and challenging reaction steps. The Blacquiere group previously synthesized a phosphine 1-azaallyl (P^AzA) ligand, in which the 1-azaallyl (1-AzA) moiety reversibly switches between multiple coordination modes. The previous phenyl-linked P^AzA ligand led to a variety of coordination modes with Pd, however the k1-P;η3-NCC mode was never observed. In pursuit of accessing the k1-P;η3-NCC coordination mode, a new P^AzA ligand bearing a biaryl backbone was targeted. The coordination chemistry of the biaryl P^AzA ligand with Pd was explored. Small molecule reactivity with the biaryl Pd P^AzA complex was examined, with the goal of inducing a change in ligand coordination mode. Preliminary catalysis with the biaryl Pd P^AzA complex was assessed.

Summary for Lay Audience

Catalysis is the process of increasing the speed of a chemical reaction with the participation of a compound known as a catalyst. During a chemical reaction, catalysts must be reactive under the given conditions to facilitate a specific chemical transformation. However, there are no permanent chemical changes made to the catalyst itself and the catalyst is not consumed. Transition metal complexes operate as very effective catalysts for several organic reactions. Transition metal catalysts are made up of two components, the metal centre and the ligands bound to the metal centre. The ligands bound to the metal centre of a transition metal catalyst can significantly influence the reactivity of the catalyst. Certain ligand families can dynamically change how they bind to a metal centre, based on the reaction environmental demands, to facilitate and stabilize difficult chemical transformations. This work focuses on expanding a new ligand family, with this dynamic metal binding ability, known as the phosphine 1-azaallyl (P^AzA) ligand family. Specifically, the synthesis of a new P^AzA ligand was conducted and how the P^AzA ligand binds to Pd was analyzed. Several reactivity experiments were investigated with this new Pd P^AzA complex, with the goal of inducing a change in how the P^AzA ligand binds to Pd. The reactivity experiments highlighted the dynamic binding ability of the P^AzA ligand, which suggested that the Pd P^AzA complex could promote desirable chemical transformations. Preliminary catalysis was attempted to try to exploit the unique reactivity of the Pd P^AzA complex.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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