Dissertation
Iron complexes as models for non-heme iron proteins
Doctor of Philosophy (Ph.D.), Drexel University
Aug 1989
DOI:
https://doi.org/10.17918/D83X11
Abstract
A series of ligands containing aromatic nitrogen donors was used to prepare iron(II) and iron(III) complexes with the aim of studying the effect of ligand composition on spin state. By substituting benzimidazole, methylbenzimidazole, or benzothiazole for one or more pyridine groups in the above ligands and by introducing methylene groups to break up the [alpha]-diimine linkage, spin-equilibrium behavior was introduced into some of these compounds in the solid state. The iron complexes are examined with Mossbauer, ESR, and electronic absorption spectroscopy and by electrochemical methods. The temperature dependence of magnetic susceptibility is measured and the causes of spin equilibrium behavior are discussed. A thermochromism study of (Fe(Bzimpy)2) (ClO4)2 is presented and the molecular structure of (Fe(Dipica)2) (BF4)2 is outlined. Several iron(III) complexes were synthesized using aromatic nitrogen and oxygen donor ligands which are mimetic of the histidine imidazole and tyrosine phenolate donors coordinated to iron in most of the non-heme, non-sulfur, iron proteins. The spectroscopic and electrochemical behavior of these compounds was examined and is compared to some of the non-heme iron-containing proteins whose active-site composition is known to some degree. A putative correlation between spin state and ligand composition is observed. Finally, a series of ligand was prepared using several substituted benzothiazolephenols and two hydroxybenzyl-benzimidazoles. Complexation of these ligands with iron(III) was found to favor formation of binuclear iron complexes with oxo or hydroxo bridges. The effect of ligand composition on the strength of antiferromagnetic coupling was examined using non-linear curve fitting of magnetic susceptibility versus temperature data to Van Vleck's equation for spin only magnetism. One electron reduction of the binuclear center is observed which parallels the behavior of some of the binuclear iron-containing proteins.
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Details
- Title
- Iron complexes as models for non-heme iron proteins
- Creators
- Curtis Wahlgren - DU
- Contributors
- Anthony William Addison (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- vii, 139 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Science (1970-1990); Drexel University
- Other Identifier
- 8168; 991014632927404721