Acid pKa Dependence in O-O Bond Heterolysis of a Nonheme FeIII-OOH Intermediate to Form a Potent FeV=O Oxidant with Heme Compound I-Like Reactivity.

08:00 EDT 12th September 2019 | BioPortfolio

Summary of "Acid pKa Dependence in O-O Bond Heterolysis of a Nonheme FeIII-OOH Intermediate to Form a Potent FeV=O Oxidant with Heme Compound I-Like Reactivity."

Protons play essential roles in natural systems in controlling O-O bond cleavage of peroxoiron(III) species to give rise to the high-valent iron oxidants that carry out the desired transformations. Herein we report kinetic and mechanistic evidence that acids can control the mode of O-O bond cleavage for a nonheme S = ½ spin FeIII-OOH species [(BnTPEN)FeIII(OOH)]2+ (2, BnTPEN = N-benzyl-N,N',N'-tris(2-pyridylmethyl)-1,2-diamino-ethane). Addition of acids having pKa values of > 8.5 in CH3CN results in O-O bond homolysis, leading to the formation of hydroxyl radicals that give rise to alcohol/ketone (A/K) ratios of around 1 in the oxidation of cyclohexane. However, the introduction of acids with pKa values of < 8.5 elicits a different outcome, namely the achievement of A/K ratios of as high as 9, the observation of rapid and catalytic hydroxylation of cyclohexane, and a million-fold acceleration in the decay rate of the FeIII-OOH intermediate at -40 °C. These results implicate the generation of a highly reactive FeV=O species via proton-assisted O-O bond heterolysis of the FeIII-OOH intermediate, which is unprecedented for nonheme iron complexes supported by neutral pentadentate ligands and serves as a nonheme analog for heme enzyme Compounds I.


Journal Details

This article was published in the following journal.

Name: Journal of the American Chemical Society
ISSN: 1520-5126


DeepDyve research library

PubMed Articles [14672 Associated PubMed Articles listed on BioPortfolio]

Substrate-triggered Formation of a Peroxo-Fe(III/III) Intermediate during Fatty Acid Decarboxylation by UndA.

The iron-dependent oxidase UndA cleaves one C3-H bond and the C1-C2 bond of dodecanoic acid to produce 1-undecene and CO. A published x-ray crystal structure showed that UndA has a heme-oxygenase-like...

Iron(II) Mediated Desulfurization of Organosulfur Substrates Produces Nonheme Diiron(II)-hydrosulfides.

A reaction system involving Fe(BF)·6HO and two dinucleating ligands, HBPMP and HPhBIMP, mediates the desulfurization of aliphatic and aromatic thiols at room temperature. This rare C-S bond cleavage ...

NMR Reveals That a Highly Reactive Nonheme Fe(IV)=O Complex Retains its 6- Coordinate Geometry and S = 1 State in Solution.

The [FeIV(O)(Me3NTB)]2+ complex (1) has been shown by Mössbauer spectroscopy to have an S = 1 ground state at 4 K, but is proposed to become an S = 2 trigonal bipyramidal species at higher temperatur...

Flavonol biosynthesis by nonheme iron dioxygenases: A computational study into the structure and mechanism.

Plants produce flavonol compounds for vital functions regarding plant growth, fruit and flower colouring as well as fruit ripening processes. Several of these biosynthesis steps are stereo- and regios...

The Mechanism of Catalytic O2 Reduction by Iron Tetraphenylporphyrin.

The catalytic reduction of O2 to H2O is important for energy transduction in both synthetic and natural systems. Herein, we report a kinetic and thermochemical study of O2 reduction catalyzed by iron ...

Clinical Trials [6328 Associated Clinical Trials listed on BioPortfolio]

Iron Bioavailability From MyPyramid Menus

This study will measure nonheme iron absorption from each of the 7 daily MyPyramid menus. Such measurements will confirm whether modifications are needed to meet dietary iron recommendatio...

Clavulanic Acid (CLAV) and Cocaine Interaction Safety Study

The main purpose of this study is to determine if it is safe to use the study drug, clavulanic acid, in combination with cocaine. In this study, subjects will receive intravenous (i.v.) co...

Open Label Pharmaco- Magnetic Resonance Spectrography (MRS) Study of Clavulanic Acid

The main purpose of this study is to determine how the study drug, clavulanic acid, affects glutamate in the brain using Magnetic Resonance (MR/MRI) scans. In this study, subjects will rec...

Validation of Brief Objective Neurobehavioral Detectors (BOND) in Mild TBI

The Veterans Health Administration (VHA) has stated the need for a brief screening instrument that can assist with the triage of the enormous number of returning OEF/OIF veterans with conc...

Clinical Evaluation of Three Dental Adhesive Systems in Class V Restorations

The purpose of this study is to compare the clinical performance of three dental adhesive systems used to bond Class V cavity fillings in adult teeth.

Medical and Biotech [MESH] Definitions

Inorganic or organic derivatives of phosphonic acid with the general formula ROP(OH)2 or RP(=O)(OH)2. The tautomeric form of this compound (P(OH)3) is PHOSPHOROUS ACIDS. Nucleoside phosphonates have a phosphate-carbon bond that is more resistant to enzymatic cleavage than the normal phosphate-oxygen bond.

Used in the form of its salts as a dye and as an intermediate in manufacture of Acid Yellow, diazo dyes, and indulines.

A dicarboxylic acid ketone that is an important metabolic intermediate of the CITRIC ACID CYCLE. It can be converted to ASPARTIC ACID by ASPARTATE TRANSAMINASE.

An intermediate in the biosynthesis of cerebrosides. It is formed by reaction of sphingosine with UDP-galactose and then itself reacts with fatty acid-Coenzyme A to form the cerebroside.

Cytoplasmic filaments intermediate in diameter (about 10 nanometers) between the microfilaments and the microtubules. They may be composed of any of a number of different proteins and form a ring around the cell nucleus.

Quick Search

DeepDyve research library

Relevant Topic

Enzymes are proteins that catalyze (i.e., increase the rates of) chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical re...

Searches Linking to this Article