The Preparation, Properties and Structure of the Iron Carbonyl Carbide Fe5(CO)15C

Braye, E. H.; Dahl, Lawrence F.; Hűbel, W.; Wampler, D. L.

doi:10.1021/ja00883a004

Cited by 184 publications

(90 citation statements)

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“…128–144 In a six-iron example, the Fe 6 cluster [Me 4 N] 2 [Fe 6 C(CO) 16 ] ( 19 , Fig. 9a) was studied in the early 1970’s as a model of possible intermediates in the iron-catalyzed Fischer-Tropsch process.…”

Section: Carbide Complexes and Fe-n2 Complexes With Carbon Ligandsmentioning

confidence: 99%

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

2016

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Nitrogenase enzymes are used by microorganisms for converting atmospheric N2 to ammonia, which provides an essential source of N atoms for higher organisms. The active site of the molybdenum-dependent nitrogenase is the unique carbide-containing iron-sulfur cluster called the iron-molybdenum cofactor (FeMoco). On the FeMoco, N2 binding is suggested to occur at one or more iron atoms, but the structures of the catalytic intermediates are not clear. In order to establish the feasibility of different potential mechanistic steps during biological N2 reduction, chemists have prepared iron complexes that mimic various structural aspects of the iron sites in FeMoco. This reductionist approach gives mechanistic insight, and also uncovers fundamental principles that could be used more broadly for small molecule activation. Here, we review recent results and highlight directions for future research. In one direction, synthetic iron complexes have now been shown to bind N2, break the N-N triple bond, and produce ammonia catalytically. Carbon and sulfur based donors have been incorporated into the ligand spheres of Fe-N2 complexes to show how these atoms may influence the structure and reactivity of the FeMoco. Hydrides have been incorporated into synthetic systems, which can bind N2, reduce some nitrogenase substrates, and/or reductively eliminate H2 to generate reduced iron centers. Though some carbide-containing iron clusters are known, none yet have sulfide bridges or high-spin iron atoms like the FeMoco.

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Section: Carbide Complexes and Fe-n2 Complexes With Carbon Ligandsmentioning

confidence: 99%

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

2016

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“…The square‐pyramidal [Fe 5 C(CO) 15 ] was the first carbonylmetal cluster containing a carbide atom to be structurally characterized. Thereafter, other carbonyliron carbide clusters were discovered, and they may be grouped into three main categories: (1) tetrairon clusters with a butterfly structure and a semi‐exposed carbide, such as [Fe 4 C(CO) 13 ], [Fe 4 C(CO) 12 ] 2– , [HFe 4 C(CO) 12 ] – ,, [HFe 4 CH(CO) 12 ]; (2) pentairon clusters with a square‐pyramidal structure and a basal semi‐exposed carbide, for example, [Fe 5 C(CO) 15 ], [Fe 5 C(CO) 14 ] 2– ; (3) the hexairon octahedral [Fe 6 C(CO) 16 ] 2– cluster featuring a fully interstitial carbide atom.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of the Highly Reduced [Fe₆C(CO)₁₅]^4– Carbonyl Carbide Cluster and Its Reactions with H⁺ and [Au(PPh₃)]⁺

et al. 2017

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The reduction of [Fe6C(CO)16]2– (1) with NaOH in DMSO or with Na/naphthalene in THF affords the highly reduced [Fe6C(CO)15]4– (2) monocarbide tetraanion. The molecular structure of 2 has been crystallographically determined as its [Et4N]4[Fe6C(CO)15]·CH3CN salt, revealing an octahedral structure as expected for a hexanuclear cluster possessing 86 valence electrons. The stepwise protonation of 2 with strong acids such as HBF4·Et2O results first in the monohydride trianion [HFe6C(CO)15]3– (3) and then the purported dihydride dianion [H2Fe6C(CO)15]2– (4), as indicated by 1H NMR spectroscopy. Both 3 and 4 are not stable enough to be isolated and rapidly decompose, yielding the parent dianion 1. The reaction of 2 with a slight excess of Au(PPh3)Cl affords the aurated dianion [Fe6C(CO)15(AuPPh3)2]2– (5), which has been isolated and structurally characterized as its [Et4N]2[Fe6C(CO)15(AuPPh3)2]·2CH3CN salt. DFT calculations allowed us to study, from a computational point of view, the electronic features of the new compounds and possible reaction intermediates.

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“…Tr eatment of the chlorostannylene cluster 3 with Na[BAr , in which the divalent Sn center migrates into the core to become the fourth basal vertex of ap seudo-square-pyramidal cluster (Figure 1). [26] TheFe À Fe distances in Fe 5 (m 5 -C)(CO) 15 and [4] + are comparable,but the larger Sn center of the latter significantly distorts the square base of the pyramid. [26] TheFe À Fe distances in Fe 5 (m 5 -C)(CO) 15 and [4] + are comparable,but the larger Sn center of the latter significantly distorts the square base of the pyramid.…”

Section: Formanydecadesinvestigationsintotheprecisetrajectoriesmentioning

confidence: 99%

“…Notably, [ 4] + is ac ationic analogue to the classical carbide cluster Fe 5 (m 5 -C)(CO) 15 in which a[ Fe(CO) 3 ]f ragment has been replaced by aSnatom. [26] TheFe À Fe distances in Fe 5 (m 5 -C)(CO) 15 and [4] + are comparable,but the larger Sn center of the latter significantly distorts the square base of the pyramid. Accordingly,t his cluster rearrangement mimics the atomicscale restructuring of metal surfaces,which has been proposed to introduce structural strain in order to optimize coordination numbers with nearest-neighbor atoms.…”

Section: Formanydecadesinvestigationsintotheprecisetrajectoriesmentioning

confidence: 99%

Controlled Expansion of a Strong‐Field Iron Nitride Cluster: Multi‐Site Ligand Substitution as a Strategy for Activating Interstitial Nitride Nucleophilicity

et al. 2018

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Multimetallic clusters have long been investigated as molecular surrogates for reactive sites on metal surfaces.Inthe case of the m 4 -nitrido cluster [Fe 4 (m 4 -N)(CO) 12 ] À ,t his analogy is limited owingtothe electron-withdrawing effect of carbonyl ligands on the iron nitride core.Described here is the synthesis and reactivity of [Fe 4 (m 4 -N)(CO) 8 (CNAr Mes2 ) 4 ] À ,a ne lectronrich analogue of [Fe 4 (m 4 -N)(CO) 12 ] À ,w here the interstitial nitride displays significant nucleophilicity.T his characteristic enables rational expansion with main-group and transitionmetal centers to yield unsaturated sites.T he resulting clusters displays urface-like reactivity through coordination-spheredependent atom rearrangement and metal-metal cooperativity.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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The Preparation, Properties and Structure of the Iron Carbonyl Carbide Fe₅(CO)₁₅C

Cited by 184 publications

References 0 publications

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

Synthesis of the Highly Reduced [Fe₆C(CO)₁₅]^4– Carbonyl Carbide Cluster and Its Reactions with H⁺ and [Au(PPh₃)]⁺

Controlled Expansion of a Strong‐Field Iron Nitride Cluster: Multi‐Site Ligand Substitution as a Strategy for Activating Interstitial Nitride Nucleophilicity

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The Preparation, Properties and Structure of the Iron Carbonyl Carbide Fe5(CO)15C

Cited by 184 publications

References 0 publications

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

Insight into the Iron–Molybdenum Cofactor of Nitrogenase from Synthetic Iron Complexes with Sulfur, Carbon, and Hydride Ligands

Synthesis of the Highly Reduced [Fe6C(CO)15]4– Carbonyl Carbide Cluster and Its Reactions with H+ and [Au(PPh3)]+

Controlled Expansion of a Strong‐Field Iron Nitride Cluster: Multi‐Site Ligand Substitution as a Strategy for Activating Interstitial Nitride Nucleophilicity

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The Preparation, Properties and Structure of the Iron Carbonyl Carbide Fe₅(CO)₁₅C

Synthesis of the Highly Reduced [Fe₆C(CO)₁₅]^4– Carbonyl Carbide Cluster and Its Reactions with H⁺ and [Au(PPh₃)]⁺