The active site of low-temperature methane hydroxylation in iron-containing zeolites

  title={The active site of low-temperature methane hydroxylation in iron-containing zeolites},
  author={Benjamin E. R. Snyder and Pieter Vanelderen and Max L. Bols and Simon D Hallaert and Lars H. B{\"o}ttger and Liviu Ungur and Kristine Pierloot and Robert A. Schoonheydt and Bert F. Sels and Edward I. Solomon},
An efficient catalytic process for converting methane into methanol could have far-reaching economic implications. Iron-containing zeolites (microporous aluminosilicate minerals) are noteworthy in this regard, having an outstanding ability to hydroxylate methane rapidly at room temperature to form methanol. Reactivity occurs at an extra-lattice active site called α-Fe(ii), which is activated by nitrous oxide to form the reactive intermediate α-O; however, despite nearly three decades of… 
Structural characterization of a non-heme iron active site in zeolites that hydroxylates methane
The geometric structure of an Fe-zeolite active site that cleaves the inert C–H bond of methane at room temperature to form methanol is defined and α-O is found to contain an unusually strong Fe(IV)=O bond resulting from a constrained coordination geometry enforced by the zeolite lattice.
Coordination and activation of nitrous oxide by iron zeolites
Iron-containing zeolites are heterogeneous catalysts that exhibit remarkable activity in the selective oxidation of inert hydrocarbons and catalytic decomposition of nitrous oxide (N2O). The
Identifying key mononuclear Fe species for low-temperature methane oxidation†
It is found that methane activation initially proceeds on the Fe site of mononuclear Fe species, which will facilitate the search towards new metal-zeolite combinations for the activation of C–H bonds in various hydrocarbons, for light alkanes and beyond.
Iron and Copper Active Sites in Zeolites and Their Correlation to Metalloenzymes.
This review identifies significant parallels and differences in the strategies used by each metallozeolite active sites to achieve high reactivity, highlighting potentially interesting mechanisms to tune the performance of synthetic catalysts.
Low-temperature selective oxidation of methane over distant binuclear cationic centers in zeolites
Highly active oxygen capable to selectively oxidize methane to methanol at low temperature can be prepared in transition-metal cation exchanged zeolites. Here we show that the α-oxygen stabilized by
Selective Formation of α-Fe(II) Sites on Fe-Zeolites through One-Pot Synthesis.
Different methods of iron introduction into zeolites are compared to derive the limiting factors of Fe speciation to α-Fe(II), and a general scheme is proposed for iron speciation in zeolite through the steps of drying, calcination, and activation.
Formation of Active Cu-oxo Clusters for Methane Oxidation in Cu-Exchanged Mordenite
Cu-exchanged zeolites are known to be active in the selective oxidation of methane to methanol at moderate temperatures. Among them, Cu-exchanged mordenite (MOR) is the system that has so far shown
Mechanism of selective benzene hydroxylation catalyzed by iron-containing zeolites
This study defines the mechanism of selective benzene hydroxylation catalyzed by Fe zeolites, clarifying the relationship between active site structure and catalytic performance (activity, selectivity), and provides a blueprint for achieving high performance in selective oxidation catalysis.
Dioxygen dissociation over man-made system at room temperature to form the active α-oxygen for methane oxidation
A cleavage of dioxygen at room temperature over distant binuclear Fe(II) species stabilized in an aluminosilicate matrix is reported, reflecting in an outstanding activity in the oxidation of methane to methanol at roomTemperature.
DFT Study on the Catalytic Activity of ALD-Grown Diiron Oxide Nanoclusters for Partial Oxidation of Methane to Methanol.
Analysis of catalytic activity of iron oxide nanoclusters that mimic the structure of the active site in the soluble form of methane monooxygenase for the partial oxidation of methane to methanol provides new insights into how they can be tuned for methane partial oxidation.


Evolution of Iron States and Formation of α-Sites upon Activation of FeZSM-5 Zeolites
Abstract Mossbauer spectroscopy in situ was used to study the effect of high-temperature activation on the evolution of iron introduced into a ZSM-5 zeolite matrix by various methods. The activation
Structure and nuclearity of active sites in Fe-zeolites: comparison with iron sites in enzymes and homogeneous catalysts.
It is concluded that Fe-ZSM-5 and Fe-silicalite are not the ideal samples conceived before and that many types of species are present, some active and some other silent from adsorptive and catalytic point of view.
Low-temperature oxidation of methane to methanol on FeZSM-5 zeolite
Chemical properties of a new form of surface oxygen (α-form) resulting from N 2 O decomposition on Fe-containing ZSM-5 zeolite were studied in the stoichiometric reaction with methane at room
Transition-metal ions in zeolites: coordination and activation of oxygen.
Two aspects of research on the TMIs Cu, Co, and Fe in zeolites are discussed: (i) coordination to the lattice and (ii) activated oxygen species.
Is [FeO](2+) the active center also in iron containing zeolites? A density functional theory study of methane hydroxylation catalysis by Fe-ZSM-5 zeolite.
It is demonstrated that this zeolite site for FeO(2+) indeed obeys the design principles for high reactivity of the FeO (2+) moiety proposed earlier: a ligand environment consisting of weak equatorial donors and very weak or absent trans axial donor.
The state of iron in the Fe-ZSM-5-N2O system for selective oxidation of methane to methanol from data of Mössbauer spectroscopy
Mossbauer spectra of Fe-ZSM-5 zeolite treated successively with N 2 O to obtain active α-oxygen and then with CH 4 were recorded. In air, the parameters of spectra significantly changed because Fe 2+
A stable molecular entity derived from rare iron(II) minerals: the square-planar high-spin-d6 Fe(II)O4 chromophore.
The first coordination compounds of this type are synthesized by employing a bis(bidentate) diolato environment with an unusually strong Jahn–Teller-initiated destabilization of the expected tetrahedral structure, which results in a high structural flexibility of the chromophore that is strongly correlated with its color.
Spectroscopic and electronic structure studies of aromatic electrophilic attack and hydrogen-atom abstraction by non-heme iron enzymes
HmaS and HPPD have similar substrate-bound complexes and that the role of the protein pocket in determining the different reactivities exhibited by these enzymes is to properly orient the substrate, allowing for ligand field geometric changes along the reaction coordinate.