Iron triphosphine complexes for the fixation of dinitrogen
File(s)
Author(s)
Fogh, Amanda
Type
Thesis
Abstract
Ammonia, which is essential for global fertiliser production and a potential zero-carbon fuel alternative, is one of the world's most produced chemicals. The Haber-Bosch process, discovered in the early 20 th century, initiated industrial-scale ammonia production from dinitrogen and dihydrogen. However, despite its century-long existence, optimisation has been stagnant, and the process still requires harsh conditions, consuming 2% of global energy and contributing 1.8% of worldwide carbon dioxide emissions annually. Homogeneous inorganic chemistry research aims to understand dinitrogen fixation at a fundamental level, potentially leading to optimised ammonia production under milder conditions. This thesis explores the chemistry of novel Fe, Co, and Ni triphosphine complexes to elucidate the effects of the ligand structure and metals on nitrogen activation. Chapter 1 introduces industrial and biological nitrogen fixation methods, the fundamental principles of dinitrogen-metal binding, and an overview of nitrogen functionalization using iron catalysts. Chapter 2 explores the synthesis and metalation of multiple triphosphine ligands on Fe, Co, and Ni using a new methodology to produce diallyl phosphine and phosphine chloride precursors. Chapter 3 investigates the formation of isostructural dinitrogen complexes using Fe, Co, and Ni, furnished with the same triphosphine ligand. Chapter 4 discusses catalytic dinitrogen silylation and compares the reactivities of the Fe, Co, and Ni complexes. Chapter 5 examines the reactivity of an iron triphosphine complex with other small molecules including carbon dioxide, dihydrogen, and carbon monoxide.
Version
Open Access
Date Issued
2025-02-24
Date Awarded
01/05/2025
License URL
Advisor
Chadwick, F. Mark
Ashley, Andrew
Crimmin, Mark
Sponsor
Imperial College London
Publisher Department
Department of Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)