Reactions of Fe+n clusters (n = 2–11) with C6H6 and C6D6. Ligand isomerization in the benzene precursor ion Fe4(C2H2)+3

Gehret, Oliver; Irion, Manfred P.

doi:10.1016/0009-2614(96)00275-8

Cited by 30 publications

(13 citation statements)

References 24 publications

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“…The calculated binding energy of Fe 4 (c-C 6 H 6 ) ϩ , 200 kJ/mol with ZPE and BSSE correction, is smaller than the experimental one, 338Ϯ48 kJ/mol. 4 This is suspicious since binding energies calculated in this study are generally overestimated by the PP86 functional when comparisons with experiments are available. From Tables III to V, we can see that the formation of benzene from Fe n (C 2 H 2 ) 3 ϩ through Fe n (n-C 4 H 4 )(C 2 H 2 ) ϩ to Fe n (n-C 6 H 6 ) ϩ and to Fe n (c-C 6 H 6 ) ϩ (nϭ2 -4) is possible from a thermodynamic point of view, even though the spin conservation principle applies.…”

Section: ¿ "Nä2 -4…mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 98%

“…They have demonstrated that benzene could be formed from ethylene under hydrogen abstraction and from cyclopropane on Fe 4 ϩ . [1][2][3][4] The formation of benzene has also been observed in the gas phase from acetylene on Fe ϩ and from ethylene on W ϩ and U ϩ . [5][6][7][8][9] Various hypotheses have been formulated to explain what is going on, but a detailed mechanism is not available yet.…”

Section: Introductionmentioning

confidence: 98%

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Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Chrétien¹,

Salahub²

2003

The Journal of Chemical Physics

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This is part of a series dealing with the formation of benzene from acetylene on iron clusters, Fenq+ (n=1–4, q=0,1). In this paper, we show that the formation of benzene from acetylene on Fe and Fen+ (n=1–4) is favorable from a thermodynamic point of view. We explain the variation of the rate constants observed for the successive adsorption of acetylene molecules on an iron cation and the experimental observations about the cyclodimerization of acetylene molecules in Fe(C2H2)2+ by referring to the spin conservation principle. Our results indicate that the complexes resulting from the cyclodimerization of Fen(C2H2)2+/Fe(C2H2)2 and Fen(C2H2)3+/Fe(C2H2)3(n=1–4) contain an n-C4H4 ligand (formation of a metallacycle) rather than a cyclobutadiene molecule. However, it is possible to observe the formation of cyclobutadiene from Fe(C2H2)2+ and Fe2(C2H2)3+ only if spin–orbit coupling is significant. A post-self-consistent-field method that includes a multideterminantal treatment is needed to get a quantitative energetic description of the various steps of the reaction. Finally, we discuss various difficulties met in this study and possible ways to deal with them.

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Section: ¿ "Nä2 -4…mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

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Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Chrétien¹,

Salahub²

2003

The Journal of Chemical Physics

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“…In particular, Irion et al (38)(39)(40) showed experimental evidence that when ethylene reacts with Fe4 + , a product of stoechiometry Fe^CeHe)" 1 ' is formed through dehydrogenation of ethylene, and benzene is released during the collision-induced dissociation experiment. In the proposed mechanism, it is acetylene rather than ethylene that is adsorbed on the Fe4 + cluster.…”

Section: Internal Proton Transfer In Malonaldehydementioning

confidence: 98%

“…Acetylene oligomerization with Fe + Cyclotrimerization of acetylene in the gas phase induced by transition metal atoms (35)(36)(37), clusters (38)(39)(40) and surfaces (41~45) is being studied intensively, but the reaction mechanism is still unknown. In particular, Irion et al (38)(39)(40) showed experimental evidence that when ethylene reacts with Fe4 + , a product of stoechiometry Fe^CeHe)" 1 ' is formed through dehydrogenation of ethylene, and benzene is released during the collision-induced dissociation experiment.…”

Section: Internal Proton Transfer In Malonaldehydementioning

confidence: 99%

Performance of Density Functional for Transition States

Salahub

Chrétien

Milet

et al. 1999

ACS Symposium Series

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An overview of the performance of GGA, hybrid and LAP density functionals for transition states in a variety of benchmark systems is given. Examples, such as hydrogen abstraction and intramolecular proton transfer in malonaldehyde, illustrate the difficulties which even the most advanced density functionals meet in describing transition states. Comparisons are also reported for the oligomerization of acetylene Fe(C 2 H 2 ) + 2 --> Fe(C 4 H 4 ) + .Advances in computational techniques and the vast experience of the past decades have allowed an understanding of catalytic reactions at a very detailed level, involving full geometry optimization, characterization of transition states (TS) and reaction intermediates (1-3). The contemporary methods of density functional theory (DFT), especially with the latest progress in the development of efficient exchange-correlation (XC) functionals, appear rather successful in these cases, embodying a large amount of electron correlation at a much lower computational cost (1-3). However, in some cases the reaction path and especially the structure and the energy of the TS may present a stringent test for the existing approximate XC functionals. A typical example is the hydrogen abstraction reaction going through one of the seemingly simplest TS structures, a linear three-atomic complex. The correct reproduction of the energy barrier for this reaction turns out to be a very difficult task not only for approximate DFT methods but also for Hartree-Fock (HF) and most of the post-HF ab initio methods (4,5). In this chapter we shed some light on why this linear three-center TS structure is so difficult to describe.Another big challenge for DFT and post-HF methods is the correct description of inter-molecular and intra-molecular proton transfer (PT) energetics. The energy barrier for the internal proton transfer (IPT) in malonaldehyde is particularly difficult

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Gasphasenkatalyse mit atomaren und Cluster‐Metall‐Ionen: ultimative “Single‐Site”‐Katalysatoren

2005

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Gasphasenexperimente mithilfe moderner massenspektrometrischer Methoden geben detaillierte Einblicke in vielerlei Elementarprozesse. Reaktionen, denen vollständige Katalysezyklen unter thermischen Bedingungen zugrunde liegen, bilden den Schwerpunkt dieses Aufsatzes. Die hier aufgeführten Beispiele decken Aspekte der Katalyse ab, die zu so unterschiedlichen Gebieten wie der Atmosphärenchemie und der Oberflächenchemie gehören. Wir werden beschreiben, wie atomare und Cluster‐Metall‐Ionen den Transfer von Sauerstoffatomen, die Aktivierung von Bindungen und die Kupplung von Fragmenten ermöglichen. Zum Teil zeigt die idealisierte Gasphasenkatalyse mit Ionen ungeahnte Analogien zu verwandten chemischen Prozessen in Lösung oder in Feststoffen, und wir lernen die intrinsischen Vorgänge an Katalysatoren auf rein molekularer Ebene besser zu verstehen.

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Reactions of Fe+n clusters (n = 2–11) with C6H6 and C6D6. Ligand isomerization in the benzene precursor ion Fe4(C2H2)+3

Cited by 30 publications

References 24 publications

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Kohn–Sham density-functional study of the formation of benzene from acetylene on iron clusters, Fe/Fen+ (n=1–4)

Performance of Density Functional for Transition States

Gasphasenkatalyse mit atomaren und Cluster‐Metall‐Ionen: ultimative “Single‐Site”‐Katalysatoren

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