Formation and Reactivity of Gaseous Iron‐Sulfur Clusters

Koszinowski, Konrad; Schröder, Detlef; Schwarz, Helmut

doi:10.1002/ejic.200300480

Cited by 19 publications

(14 citation statements)

References 33 publications

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“…140 In contrast, Freiser and coworkers focused on the cationic iron-sulfur dimer FeS + and demonstrated the ability of this dimer to activate the strong C-H bond of a variety of linear, cyclic, and branched alkanes primarily under formation of H 2 S. 142 Under similar reaction conditions Schwarz and coworkers showed the activation of the alkene 1,4-cyclohexadiene by Fe 2 S 2 + . 143 These few examples already demonstrate the capability of isolated Fe x S y clusters for C-H bond activation under mild reaction conditions. However, naturally occurring iron-sulfur enzymes like, e.g., nitrogenases and hydrogenases usually not only contain Fe x S y centres but additional metal ions such as molybdenum, vanadium, and nickel.…”

Section: B Cluster Model Systems For Biocatalysismentioning

confidence: 96%

Gas phase metal cluster model systems for heterogeneous catalysis

Lang

Bernhardt

2012

Phys. Chem. Chem. Phys.

346

291

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Since the advent of intense cluster sources, physical and chemical properties of isolated metal clusters are an active field of research. In particular, gas phase metal clusters represent ideal model systems to gain molecular level insight into the energetics and kinetics of metal-mediated catalytic reactions. Here we summarize experimental reactivity studies as well as investigations of thermal catalytic reaction cycles on small gas phase metal clusters, mostly in relation to the surprising catalytic activity of nanoscale gold particles. A particular emphasis is put on the importance of conceptual insights gained through the study of gas phase model systems. Based on these concepts future perspectives are formulated in terms of variation and optimization of catalytic materials e.g. by utilization of bimetals and metal oxides. Furthermore, the future potential of bio-inspired catalytic material systems are highlighted and technical developments are discussed.

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Section: B Cluster Model Systems For Biocatalysismentioning

confidence: 96%

Gas phase metal cluster model systems for heterogeneous catalysis

Lang

Bernhardt

2012

Phys. Chem. Chem. Phys.

346

291

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“…Keywords: ammonia · density functional calculations · dinitrogen · molybdenum · reaction mechanisms to facilitate the study of dinitrogen reduction under better controllable conditions, the process may even be considered with the simplest activation reagents, namely with bare metal atoms, which can be studied in the matrix [17] or in the gas phase. [25][26][27][28][29] Nonetheless, Schrocks catalyst allows us to investigate the principles of mild dinitrogen activation and reduction for a fully fledged homogeneous-phase catalyst.…”

Section: Introductionmentioning

confidence: 99%

A Stable Six‐Coordinate Intermediate in Ammonia–Dinitrogen Exchange at Schrock's Molybdenum Catalyst

Schenk

Kirchner

Reiher

2009

Chemistry A European J

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In this work, we investigate the mechanism of the ammonia-dinitrogen exchange reaction, which is the decisive step to close the catalytic cycle of Schrock's dinitrogen reduction sequence under ambient conditions. We identify several viable pathways for the approach of dinitrogen to the five-coordinate molybdenum center of the ammonia complex by means of first-principles molecular-dynamics simulations. These exploratory simulations are then complemented by rigorous quantum-chemical structure optimizations. Our calculations have been performed for the full Schrock catalyst without simplifying the large chelate ligand, and are hence not affected by model assumptions. We show that the reaction obeys an addition-elimination mechanism via a stable six-coordinate intermediate. This intermediate has been fully characterized by stationary quantum-chemical methods. The predicted infrared spectrum of this species features an N[triple bond]N stretching vibration, which is well separated in frequency from all other N[triple bond]N stretching vibrations of N(2)-binding complexes involved in the Schrock cycle. Depending on the life time of this intermediate in the reaction liquor, the production of this intermediate might even be monitored by the absorption of the N[triple bond]N stretching vibration.

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“…Toward this goal we intend to pursue a completely new approach by mimicking the catalytically active centers of iron-sulfur proteins in the form of gas phase clusters and by studying their intrinsic redox activity and catalytic properties. Since both theoretical and experimental studies on the structure [3][4][5][6][7] and reactivity [8][9][10][11][12][13][14] of free iron-sulfur clusters are still scarce and have only been reported for selected systems, comprehensive investigations of the influence of cluster size, composition and charge on the cluster properties are of particular interest. This will allow to gain insight into fundamental processes on a strictly molecular level and to develop general concepts.…”

Section: Introductionmentioning

confidence: 99%