1. Introduction
The oxidation of organic compounds is an important and widely used reaction in laboratory
scale organic synthesis as well as in large scale chemical industry.1,2 There are hundreds of
different reagents and methods available for the oxidation of organic chemicals. Even though
these methods exist and are very applicable for a laboratory scale, most of them share
common disadvantages from an industrial point of view. Many industrial oxidation reactions
are currently performed with a stoichiometric amounts of oxidants such as peroxides or high
oxidation state metal oxides. These oxidants are expensive and the processes where these
oxidants are used generate organic and heavy metal waste.3 When reactions are scaled to tons
instead of grams, the use of stoichiometric oxidants is not an attractive option. For these kind
of reactions an alternative and environmetally benign oxidant is welcome.
An ideal oxidant for any large scale oxidation reaction should be easily accessible, cheapand
non-toxic. As it happens, the best oxidant to fit this description is dioxygen.4 It is easily
available since it is present in air and the only by-product produced from its decomposition is
water. There are few things however which make the use of molecular oxygen challenging: 1)
although dioxygen has a high oxidation potential, it is not very reactive towards organic
molecules, 2) the reactions where dioxygen is present are often radical reactions, which are
hard to control. What is needed for efficient use of dioxygen is the appropriate catalyst which
activates the dioxygen molecule and mediates the oxidation potential to right oxidation
reaction.
Currently dioxygen is in use in several large-scale oxidation reactions, catalysed by inorganic
heterogenous catalysts.5 Typically these reactions are carried out at high temperatures and
pressures, often in the gas phase. Unfortunately, these heterogenous oxidation methods are not
suitable for reactions required by fine chemical industry, where selectivity and mild reaction
conditions are favoured in the production of high value products. If the stoichiometricoxidants are to be replaced by dioxygen, catalysts which are able to activate dioxygen at mild
reaction conditions and in solution phase are required. The most promising solution to this
challenge is homogeneous transition metal complexes which are able to catalyse selective
oxidation reactions under mild conditions by using dioxygenoxidants are to be replaced by dioxygen, catalysts which are able to activate dioxygen at mild
reaction conditions and in solution phase are required. The most promising solution to this
challenge is homogeneous transition metal complexes which are able to catalyse selective
oxidation reactions under mild conditions by using dioxygenstate of transition metal complex catalyzed oxidation research is given in the Background
section. The area of homogeneous catalytic oxidations is vast and it is too extensive to be
discussed here thoroughly. Therefore only the catalysts which are able to activate dioxygen
and contain cobalt, copper or iron are discussed herein. In the Experimental part, research
methods used in the experimental work of this thesis and the key results are introduced. The
significance of the findings made in the experimental work and its importance to the field of
catalytic oxidation research is summed up in the Conclusions section