The [2:2] Site-Differentiated Clusters [Fe4S4L2(RNC)6] Containing Two Low-Spin Iron(II) Sites

Goh, Christopher; Weigel, John A.; Holm, R. H.

doi:10.1021/ic00100a008

Cited by 27 publications

(27 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cluster 3 and its monoanionic analogue were examined by zero‐field 57 Fe Mössbauer spectroscopy to determine the oxidation states of the iron centers (Figure , Figure S5 and Table ). The isomer shift (δ)=0.33 mm s −1 for 3 is as expected for high‐spin Fe III in an anionic sulfur environment . A similar value is also reported for the Fe III –Fe III pair of the valence localized Fe III ions of the [Fe 4 S 4 (STip) 4 ] 1− cluster, and for the localized Fe III centers of the incomplete cubane [Fe 3 S 4 ] 0 clusters ,.…”

Section: Figuresupporting

confidence: 82%

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

et al. 2018

View full text Add to dashboard Cite

An unprecedented, super oxidized all-ferric iron-sulfur cubanoid cluster with all terminal thiolates, Fe S (STbt) (3) [Tbt=2,4,6-tris{bis(trimethylsilyl)methyl}phenyl], has been isolated from the reaction of the bis-thiolate complex Fe(STbt) (2) with elemental sulfur. This cluster 3 has been characterized by X-ray crystallography, zero-field Fe Mössbauer spectroscopy, cyclic voltammetry, and other relevant physico-chemical methods. Based on all the data, the electronic ground state of the cluster has been assigned to be S =0.

show abstract

Section: Figuresupporting

confidence: 82%

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

et al. 2018

View full text Add to dashboard Cite

show abstract

“…5c). While the 3:1 ratio could be taken to imply that the Fe 3+ site is the central NH 2 -bound iron, its isomer shift is inconsistent with previous four-coordinate Fe 3+ sulfide sites (~0.3 mm/s) 6,48 . Therefore, we suggest that the hole is delocalized over the three peripheral Fe sites, with averaged oxidation states of +2.33, while the central iron is high-spin Fe 2+ .…”

Section: Reactivity With N-n Bondsmentioning

confidence: 75%

Planar three-coordinate iron sulfide in a synthetic [4Fe-3S] cluster with biomimetic reactivity

et al. 2019

View full text Add to dashboard Cite

Iron-sulfur clusters are emerging as reactive sites for the reduction of small-molecule substrates. However, the four-coordinate iron sites of typical iron-sulfur clusters rarely react with substrates, implicating three-coordinate iron. This idea is untested because fully sulfide-coordinated threecoordinate iron is unprecedented. Here we report a new type of [4Fe-3S] cluster featuring an iron center with three bonds to sulfides. Although a high-spin electronic configuration is characteristic of other iron-sulfur clusters, the planar geometry and short Fe-S bonds lead to a surprising lowspin electronic configuration at the three-coordinate Fe center as determined by spectroscopy and ab initio calculations. In a demonstration of biomimetic reactivity, the [4Fe-3S] cluster reduces hydrazine, a natural substrate of nitrogenase. The product is the first example of NH 2 bound to an iron-sulfur cluster. Our results demonstrate that three-coordinate iron supported by sulfide donors is a plausible precursor to reactivity in iron-sulfur clusters like the FeMoco of nitrogenase. Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

show abstract

“…): 1.84(3) Å), all of which adopt a local low-spin configuration. [46][47][48][49][50] Outside of its unprecedented nature in the Fe-S cluster literature, 5 is an uncommon example of a structurally characterized, terminal Fe isocyanide complex with a high-spin ground state. [52][53][54][55][56] To determine if the binding of a single equivalent of t BuNC in 5 is indeed dictated by the steric pressure imposed by the IMes ligands, we carried out halide abstraction from 1 with NaBAr F 4 in the presence of excess t BuNC (Scheme 3B).…”

Section: Resultsmentioning

confidence: 99%

Controlling Substrate Binding to Fe₄S₄ Clusters through Remote Steric Effects

Brown

Suess

2019

Inorg. Chem.

View full text Add to dashboard Cite

The extraordinary reactivity exhibited by many Fe-S enzymes is due in large part to the influence of the protein scaffold on substrate binding and activation. In principle, the coordination chemistry of synthetic Fe-S clusters could similarly be controlled through remote steric effects. Toward this end, we report the synthesis of 3:1 site-differentiated [Fe4S4] clusters ligated by Nheterocyclic carbene (NHC) ligands with variable steric profiles: IMes (1,3-dimesitylimidazol-2ylidene) and I i Pr Me (1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene). Treatment of (IMes)3Fe4S4Cl with NaBAr F 4 in ethereal solvents (Et2O and THF) leads to the formation of an ether adduct, [(IMes)3Fe4S4(solv)][BAr F 4]; solvent can be displaced by addition of t BuNC to form the unusual mono-isocyanide adduct [(IMes)3Fe4S4(CN t Bu)][BAr F 4]. Carrying out the same reactions with the less sterically encumbered cluster (I i Pr Me)3Fe4S4Cl results in more typical reactivity: undesired ligand redistribution to form the homoleptic cluster [(I i Pr Me)4Fe4S4][BAr F 4] and generation of the tri-isocyanide adduct [(I i Pr Me)3Fe4S4(CN t Bu)3][BAr F 4]. The increased steric profile of the IMes ligands disfavors ligand redistribution and defines a binding pocket at the apical Fe, thereby enabling the generation of a coordinatively unsaturated and substitutionally labile Fe site. This method of controlling the coordination chemistry at the apical Fe site by modifying the sterics of ligands bound to adjacent Fe sites complements existing strategies for generating sitedifferentiated Fe-S clusters and provides new opportunities to direct reactivity at cuboidal metalloclusters.

show abstract

The [2:2] Site-Differentiated Clusters [Fe4S4L2(RNC)6] Containing Two Low-Spin Iron(II) Sites

Cited by 27 publications

References 2 publications

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

Planar three-coordinate iron sulfide in a synthetic [4Fe-3S] cluster with biomimetic reactivity

Controlling Substrate Binding to Fe₄S₄ Clusters through Remote Steric Effects

Contact Info

Product

Resources

About

The [2:2] Site-Differentiated Clusters [Fe4S4L2(RNC)6] Containing Two Low-Spin Iron(II) Sites

Cited by 27 publications

References 2 publications

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [FeIII4S4(SAr)4]

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [FeIII4S4(SAr)4]

Planar three-coordinate iron sulfide in a synthetic [4Fe-3S] cluster with biomimetic reactivity

Controlling Substrate Binding to Fe4S4 Clusters through Remote Steric Effects

Contact Info

Product

Resources

About

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

Synthesis of an All‐Ferric Cuboidal Iron–Sulfur Cluster [Fe^III₄S₄(SAr)₄]

Controlling Substrate Binding to Fe₄S₄ Clusters through Remote Steric Effects