An exploration of Iron(III) complexes with phenylpyrazole-derived ligands : insights from classical redox analyses and advanced NMR-spectroscopy / Tanja Hirschhausen ; [Chairman: Prof. Dr. Jan Paradies, First Reviewer: Prof. Dr. Matthias Bauer, Second Reviewer: PD Dr. Hans Egold, Third Reviewer: Prof. Dr. Martin Brehm]