Small molecule activation and reduction using non-heme iron complexes
type: CreativeWork
description: In Nature, metalloenzymes are responsible for carrying out a vast array of different reactions. The secondary coordination sphere of these play an intricate role in controlling nuclearity, enhancing substrate selectivity, stabilizing reactive intermediates, and controlling the redox potential of the active site metal. Many of these secondary sphere interactions are hydrogen bonding networks formed by strategically located amino acid residues. Inspired by these intricate networks, our group designed a tripodal, tetradentate ligand featuring a secondary coordination sphere through a tautomerizable framework. Each ligand arm incorporates a pyrrole-imine, which upon anionic coordination to a metal center places a hydrogen-bond acceptor in the secondary sphere. Tautomerization to the azafulvene-amine enables dative coordination and places a hydrogen-bond donor in the secondary coordination sphere. Previous work details metalation strategies allowing for both tautomeric forms of the ligand and demonstrating the independent tautomerization of each arm to form mixed tautomer species. Further work investigated the role of the secondary coordination sphere in stabilizing reactive species, such as a terminal iron(III)-oxo species. Using this ligand framework, our lab previously reported the syntheses of a series of metal complexes featuring pseudohalide ligands. In each of these complexes, hydrogen bonding interactions between the bound substrate and the ligand arms stabilized each species. In Chapter 2, the role of these interactions and the ability of the secondary coordination sphere protons to transfer to a substrate is explored through the aspatial reduction of an iron-azide complex. Reduction of the azide substrate results in fragmentation to N2 and NH3. The protons necessary to afford ammonia derive directly from the secondary coordination sphere. Isotopic labeling studies confirm the source of ammonia as the bound nitrogen atom of the azide substrate. Additionally, den…
abstract: In Nature, metalloenzymes are responsible for carrying out a vast array of different reactions. The secondary coordination sphere of these play an intricate role in controlling nuclearity, enhancing substrate selectivity, stabilizing reactive intermediates, and controlling the redox potential of the active site metal. Many of these secondary sphere interactions are hydrogen bonding networks formed by strategically located amino acid residues. Inspired by these intricate networks, our group designed a tripodal, tetradentate ligand featuring a secondary coordination sphere through a tautomerizable framework. Each ligand arm incorporates a pyrrole-imine, which upon anionic coordination to a metal center places a hydrogen-bond acceptor in the secondary sphere. Tautomerization to the azafulvene-amine enables dative coordination and places a hydrogen-bond donor in the secondary coordination sphere. Previous work details metalation strategies allowing for both tautomeric forms of the ligand and demonstrating the independent tautomerization of each arm to form mixed tautomer species. Further work investigated the role of the secondary coordination sphere in stabilizing reactive species, such as a terminal iron(III)-oxo species. Using this ligand framework, our lab previously reported the syntheses of a series of metal complexes featuring pseudohalide ligands. In each of these complexes, hydrogen bonding interactions between the bound substrate and the ligand arms stabilized each species. In Chapter 2, the role of these interactions and the ability of the secondary coordination sphere protons to transfer to a substrate is explored through the aspatial reduction of an iron-azide complex. Reduction of the azide substrate results in fragmentation to N2 and NH3. The protons necessary to afford ammonia derive directly from the secondary coordination sphere. Isotopic labeling studies confirm the source of ammonia as the bound nitrogen atom of the azide substrate. Additionally, den…
author: Miller, Tabitha J
language: en
keywords: chemistry, inorganic chemistry, bioinorganic chemistry, oxyanions, small molecule activation
date published: 2021-09-17T02:34:12Z
date modified: 2026-07-22T22:24:52Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/110624