Ph.D. Thesis
Title Reactions of the Iron (III) Hydroxo Dimer
with Inorganic Ligands
Advisers Prof. Istv�n F�bi�n
Thesis Committee Prof. F. Jo�, Department of Physical Chemistry;
Prof. I. S�v�g�, Department of Inorganic and Analytical Chemistry;
Dr. L. Soms�k, Department of Organic Chemistry, University of Debrecen;
Dr. Tam�s Tur�nyi, E�tv�s Lor�nd University; Prof. Gy�rgy Bazsa, Department
of Physical Chemistry, University of Debrecen; Dr. Ott� Horv�th, Department
of General and Inorganic Chemistry, University of Veszpr�m
Essay
Iron is the most abundant transition element in the
solar system and on the earth. In the oxidative atmosphere of our
planet it mostly occurs in the oxidation state of +3. The metal has
been known to humankind since ancient times and has had an immense
impact on history and culture. Iron is classified as essential in
biological systems, where it is often found in oxo- or hydroxo-bridged
di- or oligonuclear structures. Numerous enzymes with dinuclear iron(III)
centers are known and their structural motifs can be used to design
protein-free dinuclear iron(III) catalysts.
Iron(III) gives rise to polynuclear species in aqueous
solution over a characteristic pH range. Mononuclear hydrolytic species
are important in the kinetics and mechanism of substitution and redox
reactions. It seems to be reasonable that polynuclear hydrolytic complexes
may also have similar roles.
The major goal of this thesis was to characterize the
kinetics and equilibrium of direct ligand substitution reactions of
the aqueous iron(III) hydroxo dimer, Fe2(�-OH)2(H2O)84+
, with simple inorganic ligands and draw structural and mechanistic
conclusions from the results. A further objective was to explore the
possible role of Fe2(OH)24+ in redox
reactions between iron(III) and inorganic species with special emphasis
on the iron(III) - sulfur(IV) system because of its outstanding environmental
significance. Because of the complexity of the studied reactions,
the traditional kinetic evaluation method based on pseudo first-order
curves could only be employed in a few cases, and the rate constants
in other systems were calculated by fitting the experimental kinetic
traces directly to the simultaneous differential equations defined
by the kinetic model.
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The thesis was written in English. The full text, the
English and the Hungarian abstracts of the thesis were published on
the Internet. They can be downloaded from the personal homepage of
the author <http://www.klte.hu/~lenteg/index.html>.
