Elucidation of mechanisms in manganese and iron based oxidation catalysis: Mechanistic insights and development of novel approaches applied to transition metal catalyzed oxidations catalysis

Oxidation chemistry is central to life and to the modern chemical industry and hence understanding chemical oxidation is essential to developing new processes and elucidating biological oxidation mechanisms. Elucidating mechanisms in inorganic oxidation catalysis and simultaneously developing new tools to do so is the theme of this thesis. Spectroscopic techniques, especially Raman and UV-vis absorption, are used, together with Density Functional theory (DFT), to observe and characterise the changes that occur in the structure of manganese and iron catalysts when reacting with hydrogen peroxide and bleach. The introduction provides a brief overview of the techniques used with the second and the third chapters focused on DFT calculations on iron complexes, including the first iron complex with bleach (hypochlorite), and the mechanisms by which the complexes react with hypochlorite, hydrogen peroxide and oxygen. In the fourth and fifth chapters, our understanding of industrially applied manganese catalysts is depended in a combined UV-vis absorption, (resonance) Raman and EPR spectroscopic study, with the goal of identifying the species responsible for the oxidation of organic substrates especially alkenes with hydrogen peroxide. In the final chapters attention is turned to developing new physical tools to extract real time information on reaction progress in complex media such as two phase reactions and molecular tools to gain insight into the nature of the species that are not observable due to their very short lifetimes. Overall the work described in this thesis is to understand more deeply the fundamental nature of catalysts’ reactivity with the goal of making better catalysts and cleaner chemical conversions.