This thesis discusses reduction and oxidation reactions catalysed by the perrhenate
anion and oxidation reactions catalysed by other oxo-anions i.e. sulfate and nitrate.
Chapter one introduces catalytic hydrosilylation, hydroboration, deoxydehydration
and alkene epoxidation and some of their applications, with a focus on high oxidation
state complexes.
Chapter two describes the synthesis of a salt of perrhenate [N(hexyl)4][ReO4] which is
highly soluble in organic solvents. The use of this salt as a catalyst for both the
hydrosilylation and hydroboration of carbonyl compounds and carbon dioxide is
discussed. Catalytic methylation of amines and anilines with carbon dioxide and
hydrosilanes is also reported. Labelled carbon dioxide reactions and DFT calculations
are conducted in order to understand the mechanism of carbon dioxide reduction using
hydrosilanes.
Chapter three outlines the synthesis of a number of alkylammonium and pyridinium
perrhenate salts and their application in the deoxydehydration reaction, converting
vicinal diols to alkenes. The role of the counterion is discussed with pyridinium
perrhenates shown to be more effective catalysts. DFT calculations are conducted to
identify the most likely pathway of the catalytic cycle. Alternative reducing agents to
the triphenylphosphine initially used are also studied.
Chapter four reports results of organic salts of perrhenate, sulfate and nitrate as
oxidation catalysts, specifically their ability to catalyse epoxidations of alkenes. By
the formation of supramolecular ion pairs (SIPs), these anions are made organic
soluble which is found to significantly enhance their catalytic ability, however, the
organic counterions used to form these SIPs were found to be of importance. Ionic
liquids are also used for the epoxidation of alkenes. Solution studies are presented to
further understanding of how these compounds interact with one another in solution.
Chapter five contains experimental conditions and characterisation for compounds
discussed in this work
