Model complexes for active sites of diiron metalloproteins, dioxygen reactivity and water effects

(cont.) tetrairon(II) cubane complex was identified and structurally characterized. Chapter 4: Synthesis and Characterization of [Fe₂...CR)]³⁺ and [Fe₂...CR)]³⁺ Complexes with Carboxylate-Rich Metal Coordination Environment as Models for Diiron Centers in Oxygen-Dependent Non-Heme Enzymes. Utilizing hydrogen bonding interactions and sterically bulky carboxylates, synthetic routes were developed to prepare the mononuclear iron(II) complexes with the vacant coordination sites for O₂ binding. Reactions of such complexes with O₂ resulted in rare asymmetric complexes having an [Fe₂...CR)]³⁺ or [Fe₂...CR)]³⁺ unit. These diiron(III) complexes with carboxylate-rich metal coordination environments reproduce the diiron(III) cores housed in four-helix bundles found in nature. Compound 3, which replicates the [Fe₂...CR)] core of sMMOH[ox], shares several physical properties with the enzyme, electronic transitions, Mossbauer spectra, and magnetic exchange interactions. On the other hand, the structure of 4, ([mu]-oxo)([mu]-carboxylato)diiron(III) complex, mimics the diiron(III) sites of RNR-R2. The electronic and Mbssbauer spectral transitions of 4 are typical of diiron(III) complexes with an Fe-O-Fe moiety. Magnetic exchange coupling interaction between the two iron atoms is within the expected range for oxo-bridged diiron(III) sites. These results demonstrate how the diiron(III) structures in different metalloproteins, namely, the [mu]-oxo cores of RNR-R2 and the [mu]-dihydroxo unit in MMOH, can be replicated by subtle changes in ligand composition ...

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Yoon, Sungho, 1971-

Advisor dc:contributor.advisor

• Stephen J. Lippard.

• Chemistry.

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• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28696

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28696