Modeling the active sites of non-heme diiron metalloproteins with sterically hindered carboxylates and syn N-Donor ligands

Chapter 1. Different Synthetic Approaches to Modeling the Active Sites of Carboxylate-Bridged Non-Heme Diiron Enzymes Carboxylate-bridged non-heme diiron enzymes activate dioxygen to perform a variety of biological functions. Synthetic model compounds have been prepared to gain insight into the intricacies of dioxygen activation in these enzymes. In this introductory chapter, the challenges and advances of different diiron systems with terphenyl and dendrimer-appended carboxylates, nitrogen-rich, and syn Ndonor ligands are highlighted. Chapter 2. 9-Triptycenecarboxylate-Bridged Diiron(ll) Complexes: Capture of the Paddlewheel Geometric Isomer The synthesis and characterization of diiron(ll) complexes supported by 9- triptycenecarboxylate ligands (-O2CTrp) is described. The interlocking nature of the triptycenecarboxylates facilitates formation of quadruply bridged diiron(ll) complexes of the type [Fe 2(-O 2CTrp) 4(L) 2] (L = THF, pyridine or imidazole derivative) with a paddlewheel geometry. A systematic lengthening of the Fe-Fe distance occurs with the increase in steric bulk of the neutral donor L, resulting in values of up to 3 A without disassembly of the paddlewheel structure. Reactions with an excess of water do not lead to decomposition of the diiron(ll) core, indicating that these quadruply bridged complexes are exceptionally stable. The red-colored complexes [Fe2(f-O2CTrp) 4(4-AcPy) 2] (10) and [Fe2(M-O2CTrp)4(4- CNPy)2] (11) exhibit solvent-dependent thermochromism in coordinating solvents that was studied by variable temperature UV-vis spectroscopy.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Friedle, Simone, 1976-

Advisor dc:contributor.advisor

• Stephen J. Lippard.

• Chemistry.

Statement dc:rights

• 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

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/55086

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/55086