Chemical Models, Theoretical Calculations, and the Reactivity of Isolated Iron-Molybdenum Cofactor

Barrière, Frédéric; Durrant, Marcus C.; Pickett, Christopher J.

doi:10.1007/978-1-4020-3611-8_7

Cited by 6 publications

(2 citation statements)

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“…22−25 However, more structurally relevant models comprising multiple metal atoms and a sulfur environment appeared to lose the ability to bind N 2 , which of course represents one of the foundations of functional relevance. 22,26 Only very recently has a novel model complex been synthesized that is able to bind N 2 . This model includes iron−sulfur carbon sites and thus successfully accounts for the sulfur environment of iron in nitrogenase; however, it contains only one iron center and does not consider the presence of multiple metal atoms.…”

Section: Introductionmentioning

confidence: 99%

“…With the aim of gaining a fundamental understanding of the nitrogen binding and the subsequent ammonia synthesis mechanism, numerous model complexes have been synthesized during the last decades. Surprisingly, simple metal atom complexes have been found to bind N 2 and have provided important insight into the catalytic reaction mechanism for N 2 reduction. − However, more structurally relevant models comprising multiple metal atoms and a sulfur environment appeared to lose the ability to bind N 2 , which of course represents one of the foundations of functional relevance. , Only very recently has a novel model complex been synthesized that is able to bind N 2 . This model includes iron–sulfur carbon sites and thus successfully accounts for the sulfur environment of iron in nitrogenase; however, it contains only one iron center and does not consider the presence of multiple metal atoms .…”

Section: Introductionmentioning

confidence: 99%

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Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase

et al. 2016

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The active centers of the nitrogen-fixing enzymes nitrogenases comprise iron−sulfur clusters. The binding of the substrate N 2 to these clusters plays a fundamental role for the subsequent ammonia synthesis. However, due to the complexity of the natural system and the lack of suitable synthetic models, the interaction of N 2 with the iron−sulfur clusters remains largely elusive. In this contribution, we demonstrate the gas-phase preparation and investigation of the cationic Fe 2 S 2 + , Fe 3 S 3 + , and Fe 4 S 4 + clusters. These clusters represent the first cluster model systems containing more than one iron and sulfur atom, respectively, which are found to bind N 2 . Temperature-dependent kinetic measurements allow, for the first time, for the determination of experimental binding energies of N 2 to iron−sulfur clusters. In addition, concurrent firstprinciples simulations reveal the ground state and isomeric structures of the iron−sulfur clusters with and without adsorbed N 2 and provide a conceptual understanding of the interaction between N 2 and iron−sulfur clusters. In particular, we present molecular level details of N 2 bonding such as the identification of the adsorption sites, the bond geometry, the bond strength, and the nature of the cluster-N 2 binding interaction, which is found to be promoted by occupation of the empty antibonding orbitals of the free N 2 molecule through interaction with the frontier orbitals of the iron−sulfur complex involving d-orbitals of iron hybridized with sulfur porbitals.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase

et al. 2016

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Nitrogenase: Metal Cluster Models

Barri��re¹

2005

Encyclopedia of Inorganic Chemistry

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This article reviews the synthesis and properties of inorganic clusters that model the iron–sulfur centers found in the nitrogenase enzyme. These sites are of the Fe 4 S 4 , Fe 8 S 7 , and MoFe 7 S 9 stoichiometry. The enzyme [Fe 4 S 4 ] 2+/1+ center is well modeled by synthetic clusters bearing thiolate ligands at iron. However, the [Fe 4 S 4 ] 0 state is stabilized in the enzyme and has not been reproduced in the laboratory so far. Recent progress in synthetic models of the Fe 8 S 7 P‐cluster is reported. One of its known structures can be obtained by self‐assembly from basic constituents, or synthesized in a stepwise fashion from smaller clusters yielding topological analogues. The most challenging cluster to model is the FeMo‐cofactor. This MoFe 7 S 9 center is the site of dinitrogen reduction to ammonia. The cluster also exists with vanadium or iron in place of molybdenum in alternative nitrogenases. It was shown only recently that the FeMo‐cofactor is centered on a light atom that is probably a nitrogen atom. Structural modeling of this center is limited. Only its molybdenum or heterometal end has been accurately modeled. Functional chemistry of good structural models, those with sulfur ligands and metal–metal bonds, only concerns the reduction of already partially reduced diazo substrates such as diazene or hydrazine.

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Nitrogen Fixation

Newton

2005

Kirk-Othmer Encyclopedia of Chemical Technology

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Nitrogen fixation converts inert atmospheric molecular nitrogen gas into reduced forms whereby the nitrogen may be used by all life forms for protein and nucleic acid production. The biological process occurs only in microorganisms and is the principal contributor of fixed nitrogen to the biosphere. Fixed nitrogen is also derived from nonbiological processes, eg, fires, volcanoes, and lightning, and from commercial fertilizer production. The Haber‐Bosch ammonia process is highly energy efficient and is the most economical industrial process available. The most important source of biologically fixed nitrogen for agriculture is the symbiotic system that involves leguminous plants, which harbor rhizobia bacteria in nodules on their roots. Smaller contributions are made by other, less formal systems and by free‐living microbes. All of the biological systems use a similar metalloenzyme complex, called nitrogenase. Biological nitrogen fixation is discussed from a biochemical‐genetic viewpoint, as well as in terms of model chemistry and comparisons with the commercial process. Chemical approaches aimed at duplicating the biological process are also presented.

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Chemical Models, Theoretical Calculations, and the Reactivity of Isolated Iron-Molybdenum Cofactor

Cited by 6 publications

References 144 publications

Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase

Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase

Nitrogenase: Metal Cluster Models

Nitrogen Fixation

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Chemical Models, Theoretical Calculations, and the Reactivity of Isolated Iron-Molybdenum Cofactor

Cited by 6 publications

References 144 publications

Interaction of Iron–Sulfur Clusters with N2: Biomimetic Systems in the Gas Phase

Interaction of Iron–Sulfur Clusters with N2: Biomimetic Systems in the Gas Phase

Nitrogenase: Metal Cluster Models

Nitrogen Fixation

Contact Info

Product

Resources

About

Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase

Interaction of Iron–Sulfur Clusters with N₂: Biomimetic Systems in the Gas Phase