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Showing 1 to 20 of 24 for “"FeFe"”.
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Hydrides in [FeFe]-hydrogenase model complexes
The student, Michaela Carlson, submitted this Dissertation for approval on 2018-04-17 at 10:07.
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Incorporation of cyanide ligands into models of [FeFe]- and [NiFe]-hydrogenase
… hydrogenase enzymes are bimetallic with FeFe or NiFe active sites. The metals of the active sites are bound to carbonyl and cyanide ligands with the metal centers bridged by thiolates. The use of inexpensive and readily available elements by hydrogenase enzymes has been a driving force …
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Chemistry related to the actives sites of the [Fe]- and [FeFe]-hydrogenases
… to the biosynthesis of the H-cluster of [FeFe]-hydrogenase. The mechanism by which the [Fe]-hydrogenase functions is not fully understood, and biomimetic models currently offer limited insight. This emphasises the need to explore the fundamental organometallic chemistry of biologically …
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Synthetic models of [FeFe]-hydrogenase: case studies utilizing azadithiolate and nitrosyl coligands
… the redox behavior of synthetic models for the [FeFe]-hydrogenases, consisting of diiron dithiolato carbonyl complexes bearing the amine cofactor and its N-benzyl derivative. Of specific interest are the causes of the low reactivity of oxidized models toward H2, which contrasts with the high …
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Hydrogen production from model complexes of the [FeFe]- and [NiFe]-hydrogenase active sites
… to utilize molecular hydrogen as a fuel. The [FeFe]-hydrogenases predominately function to produce hydrogen from protons and electrons, while the [NiFe]-hydrogenases function to oxidize hydrogen. The active sites of both enzymes contain first-row transition metals and biologically exotic …
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A combined approach of electronic structure calculations and spectroscopy for elucidating reaction mechanisms in organic and bioinorganic systems
… and energy harvesting. The mechanisms by which [FeFe] and [NiFe] hydrogenase enzymes catalyse the reversible reduction of protons to dihydrogen are of intrinsic interest in the context of a developing hydrogen technology for energy transduction. Gas phase DFT calculations are used to simulate and …
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Synthesis of redox-active ligands and their use in hydrogenase modeling
… into H2. The two primary H2ases are the [FeFe] and [NiFe]-H2ases, aptly named for the metals present at the active sites. Both H2ases possess numerous unique features, including FeS cluster to relay electrons, CN and CO ligands to maintain low spin metal centers, and thiolate ligands and …
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Identification and description of Clostridium sp. and metabolic activities in fermentative hydrogen production
… three hydrogen producers, which harboured the [FeFe] hydrogenase gene, were characterised by 16S rDNA sequencing, and further physiologically identified as Clostridium sp. (W1), Clostridium butyricum (W4) and Clostridium butyricum (W5). The structure of the putative [FeFe] hydrogenase gene …
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Modeling the Active Sites of [nickel-Iron]- and [iron-Iron]-Hydrogenases
While previous hydride-containing [FeFe]-hydrogenase models featured only bridging hydrides, we sought to prepare complexes of terminal hydrides that would be more relevant to mimicking this hydrogenase. Di-subferrous precursors, such as Fe2(S2C2H4)(CO)4 (PMe3)2, have been known for decades---well …
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Hydrogenase Models and Studies Based on Iron Carbonyl Chelate Complexes
… Mossbauer or NRVS, generating new insights into [FeFe]- and Hmd-H 2ases. A comproportionation route permits selective labeling of one iron center of the diiron unit with 57Fe. Also, the comproportionation route is finding further utility in generating heterometallic dinuclear complexes.
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Small molecule mimics of hydrogenase enzymes: synthesis, protonation, and electrocatalysis
… two most prevalent hydrogenases contain NiFe or FeFe cores, bound to thiolates, cyanide, and carbon monoxide ligands. These enzymes are also rich in Fe-S clusters to allow the necessary redox chemistry of hydrogen oxidation and production. Both enzymes operate at rates and overpotentials …
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Hydrogen Production From Model Complexes of the [iron-Iron]- and [nickel-Iron]-Hydrogenase Active Sites
Unlike the [FeFe]-hydrogenases, model complexes for the [NiFe]-hydrogenases were unknown prior to the crystal structure in 1996. However, most synthetic efforts focused on structural models for the active site, and neglected the catalytically imperative hydride ligand. Thus, we sought a nickel-iron …
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Spectroscopic studies on hydrogenases
… was applied for the first time on the [FeFe] hydrogenase from Chlamydomonas reinhardtii (HydA1), the smallest catalytic unit of this class of hydrogenase, revealing thereby the first catalytic intermediate in the proton reduction reaction. RR spectroscopy was initially used to …
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Metabolic and molecular responses to interspecies hydrogen transfer between Ruminococcus albus and Wolinella succinogenes
… ferredoxin- and NAD-dependent [FeFe]-hydrogenase, HydABC, couples proton reduction using nicotinamide adenine dinucleotide (NADH) to proton reduction using reduced ferredoxin (Fdred), producing molecular hydrogen: 3 H+ + NADH + Fdred → 2 H2 + NAD+ + Fdox. HydA2, a …
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Novel infrared spectroscopic techniques for the study of adsorbed proteins on photoactive thin films
… of the enzyme of interest for this work (a [FeFe]-hydrogenase from Clostridium acetobutylicum), techniques were developed in a manner conducive to anaerobic environments. Solid-state ligand exchange processes were shown to have no detrimental effect on the continued ability of nanocrystal …
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Biohydrogen production in Escherichia coli – a synthetic biology approach
… approaches were investigated. A synthetic [FeFe]-hydrogenase based on a thermostable NADH-dependent hydrogenase was designed, constructed and expressed in E. coli. The structure and activity of the synthetic hydrogenase has been characterised in vitro using a number of techniques including …
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SECONDARY INTERACTIONS WHICH MODIFY REDOX AND OTHER PROPERTIES OF ORGANOMETALLIC SYSTEMS
… cyanide in a model for the diiron subsite of [FeFe]-hydrogenase. The natural subsite in its protein environment catalyses hydrogen evolution (or uptake) at very fast rates ca 104 s-1 near the reversible potential of the H+ /1/2 H2 couple but such rates have yet to be attained in model systems. …
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Synthesis, spectroscopy, and electrochemistry of hydrogenase mimics
… these states in biological HER catalysis. The FeFe-H2ase has been shown to catalyze the HER via kinetic protonation of an azadithiolate cofactor. Extensive studies of model complexes and hybrid proteins have revealed the importance of the azadithiolate in catalyzing the HER with fast rates. …
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Reactions at coordinated ligands: redox-active ligands and coordination of Lewis acids
… Cyanide is an essential component of the [FeFe]- and [NiFe]-hydrogenase active sites, both enzymes feature two cyanide ligands, however, models using cyanides ligands are plagued by undesirable side reactions such as metal-cyanide bridged polymers and decomposition. The bound boranes are …
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Immobilising and Interfacing Poly(Heptazine Imide) Ionic Carbon Nitride for Photo(electro)catalytic Fuel and Chemical Production
… 10 hours of operation. Finally, the use of a [FeFe]-hydrogenase (H2-evolving enzyme) possessing a positive surface charge around the active site made it possible to directly interface it to the negatively charged cyanamide-modified graphitic carbon nitride (NCNCNx) as photocatalyst powder in …
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