Drawing Small Cations into Highly Charged Porous Nanocontainers Reveals “Water” Assembly and Related Interaction Problems

Müller, Achim; Krickemeyer, Erich; Bögge, Hartmut; Schmidtmann, Marc; Botar, Bogdan; Talismanova, M. O.

doi:10.1002/anie.200351126

Cited by 142 publications

(26 citation statements)

References 28 publications

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“…Thus, one can consider three different environments for the active oxidizing intermediate: (1) on the inner surface of the {Fe III 30 W VI 72 } capsule where the active oxo unit is in the axial position, O a,i ; (2) on the outer surface where the active oxo unit is in the axial position, O a,o ; or (3) in the pore where the active oxo unit is in the equatorial position, O e . In the past there have been measurements on analogous capsules with slightly larger pores, {Mo 132 }, that demonstrated by NMR measurements the encapsulation of alkanes and arenes when the inner surface was lined with acetate or propionate ligands as opposed to sulfate in the presently used {Fe III 30 W VI 72 } capsule. , The likelihood of an active oxo unit being at the O a,i position is low considering the fast reaction of bulky substrates such as cis- 4,4′-(ethene-1,2-diyl)dibenzoate. To verify this point, {Mo 132 } with sulfate ligands was prepared as an analogue of {Fe III 30 W VI 72 } since the presence of paramagnetic Fe(III) prevented direct NMR measurements .…”

Section: Resultsmentioning

confidence: 99%

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

et al. 2020

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The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various “shunt” pathways, have shown that high-valent Fe(V)O and the formally isoelectronic Fe(IV)O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron–tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom (“NIH shift”); (2) a high kinetic isotope effect for alkyl CH bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.

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Section: Resultsmentioning

confidence: 99%

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

et al. 2020

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“…NH 4 ‐1 and NH 4 ‐2 were prepared as described by Müller et al 39–40. Monodeprotonated acids NaHSucc and NaHGlu (abbreviated hereafter NaHL) are prepared by addition of one equivalent of NaOH to a suspension of H 2 Succ or H 2 Glu (typically 1 g in 40 mL of water) followed by evaporation of the solvent under vacuum.…”

Section: Methodsmentioning

confidence: 99%

Tunable Keplerate Type‐Cluster “Mo₁₃₂” Cavity with Dicarboxylate Anions

Lai

Awada

Floquet

et al. 2015

Chemistry A European J

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The internal functionalization of the Keplerate-type capsule Mo132 has been carried out by ligand exchange leading to the formation of glutarate and succinate containing species isolated as ammonium or dimethylammonium salts. Solution NMR analysis is consistent with asymmetric inner dicarboxylate ions containing one carboxylato group grafted onto the inner side of the spheroidal inorganic shell while the second hangs toward the center of the cavity. Such a disposition has been confirmed by the single-crystal X-ray diffraction analysis of the glutarate containing {Mo132 } species. A detailed NMR solution study of the ligand-exchange process allowed determining the binding constant KL of acetate (AcO(-) ), succinate (HSucc(-) ) or glutarate (HGlu(-) ) ligands at the 30 inner coordinating sites, which vary such as K AcO -

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“…The structure of the capsule is shown in Figure 6.1 a; the total charge of the capsule is −72e, where e is the charge of a proton. The atomic coordinates of the capsule were taken from an earlier publication [129].…”

Section: Chaptermentioning

confidence: 99%

Modeling the Interface between Biological and SyntheticComponents in Hybrid Nanosystems

Carr¹

2011

Simulations in Nanobiotechnology

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The fusion of biology and nanotechnology holds amazing promise for revolutionizing medicine and personal technology. In order to take advantage of the great feats of engineering coming out of these fields, there needs to be theories and computational tools capable of describing the interface between the pristine and ordered world of precision electronics and the hot, wet, and stochastic world of biology. The success of these technologies will depend on our abilities to design and optimize interactions of biomolecules and solid-state

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Drawing Small Cations into Highly Charged Porous Nanocontainers Reveals “Water” Assembly and Related Interaction Problems

Cited by 142 publications

References 28 publications

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

Tunable Keplerate Type‐Cluster “Mo₁₃₂” Cavity with Dicarboxylate Anions

Modeling the Interface between Biological and SyntheticComponents in Hybrid Nanosystems

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Drawing Small Cations into Highly Charged Porous Nanocontainers Reveals “Water” Assembly and Related Interaction Problems

Cited by 142 publications

References 28 publications

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound I Type Oxidants

Tunable Keplerate Type‐Cluster “Mo132” Cavity with Dicarboxylate Anions

Modeling the Interface between Biological and SyntheticComponents in Hybrid Nanosystems

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Product

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Tunable Keplerate Type‐Cluster “Mo₁₃₂” Cavity with Dicarboxylate Anions