Dinitrogen Splitting to Rhenium-Nitrides and Their Subsequent Functionalization

Date of Award

Fall 2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Holland, Patrick

Abstract

This thesis describes the synthesis, characterization, and reactivity of a series of rhenium complexes that were designed to study the fundamentals of N2 fixation under electrochemically relevant conditions. Chapter 1 is an introduction to the reactivity of transition-metal complexes with N2 and discusses the applications of the N2-splitting reaction to electrocatalysis. Chapter 2 describes a series of rhenium complexes bearing the P2tBuPyrr pincer ligand (P2tBuPyrr = (2,5-{tBu2PCH2}2C4H2N)–). The weak π-donating nature of the pincer-pyrrolide results in an accessible open-shell configuration which leads the formation of a rhenium(III) N2-bridged complex. Upon reduction, the P2tBuPyrr supported complex can split N2 to terminal nitrides. In Chapter 3, the series of P2tBuPyrr-rhenium complexes is expanded with the synthesis of a cationic species that bears both nitride and a, π-accepting, isocyanide ligand. This cationic complex is capable of generating NH3 in cyclic fashion. Several intermediates are isolated along this cycle including a π11 mixed valent complex. Chapter 4 builds on the newly reported nitride-isocyanide complex with the isolation of the one- and two-electron reduced forms. The electronic structure of these formally low oxidation state nitride complexes are described by computational and spectroscopic studies.

This document is currently not available here.

Share

COinS