Abstracts

This PhD thesis focuses on the development and characterization of new organometallic iron complexes as models for abundant enzymatic systems. The use of a macrocyclic tetracarbene ligand system results in novel features of the organometallic iron complexes compared to literature-known nitrogen-coordinated model compounds. In particular, the strong -donating carbene donors induce a destabilization of the d(xy) orbital and thus an increased HOMOLUMO gap in the oxoiron(IV) complex studied in this thesis. This makes the high-valent oxoiron(IV) compound a unique system which is able to activate weak CH bonds via the triplet pathway only. Moreover, mixed-valent and high-valent -nitridodiiron systems are developed and their properties are studied by a series of analytical techniques including x-ray diffraction and Mssbauer spectroscopy. Furthermore, a complete series of structurally characterized {FeNO}68 species is presented. Using a variety of spectroscopic and theoretical methods, the redox processes within this series are identified as largely metal centered. Finally, initial studies toward the development of new hybrid ligand systems combining N-donating and C-donating groups are described.Advisors/Committee Members: Meyer, Franc (advisor), Meyer, Franc (referee), Feuner, Ivo (referee), Ackermann, Lutz (referee), Schneider, Sven (referee), Siewert, Inke (referee), Demir, Selvan (referee).