The influences of carbon donor ligands on biomimetic multi-iron complexes for N2reduction

Nagelski, Alexandra L.; Fataftah, Majed S.; Bollmeyer, Melissa M.; McWilliams, Sean F.; MacMillan, Samantha N.; Mercado, Brandon Q.; Lancaster, Kyle M.; Holland, Patrick L.

doi:10.1039/d0sc03447a

Cited by 26 publications

(48 citation statements)

References 84 publications

(116 reference statements)

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“…Carbyne (5) and nitride (6) have the same charge, but result in ~1 V difference in reducing power. In contrast, nitride (6) vs imide (7) and sulfide (8) have reduction potentials within 300 mV, indicating the formal charge of the ligand does not have as large impact. The ability of the carbyne to increase the reduction power is likely a consequence of its stronger interaction with the metal centers, an aspect that will be pursued in a separate study.…”

Section: Resultsmentioning

confidence: 98%

“…Still, a difference in the (MFe3) 11+ /(MFe3) 10+ redox potentials of 1.12 V is observed, a remarkable impact of the C-vs Nbased ligands. Changing the donor from nitride (6) to imide (7) or sulfide (8) shifts the redox potential less than 200 mV highlighting the similar impact of S and N donors on the redox chemistry, in large contrast to the carbyne.…”

Section: Resultsmentioning

confidence: 99%

“…Bi-and multimetallic model systems focused on interrogating the role of the interstitial atom and multimetallic effects have been targeted 7,[9][10][11][12][13][14][15][16][17][18][19][20][21][22] , but complexes that display bridging carbide 11,[23][24][25][26] or even carbyne 9,10,27 ligands are rare. Carbide-containing Fe clusters display four to six metal centers, but invariably are rich in CO ligands.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Cluster Models of FeMoco with Sulfide and Carbyne Ligands: Effect of Interstitial Atom in Nitrogenase Active Site

Le¹,

Bailey²,

Scott³

et al. 2021

Preprint

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Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an iron-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMoco displays eight metal centers bridged by sulfides and a carbide having the MoFe7S8C cluster composition. The role of the carbide ligand, a unique motif in protein active sites, remains poorly understood. Toward addressing its function, we isolated synthetic models of subsite MFe3S3C displaying sulfides and a carbyne ligand. We developed synthetic protocols for structurally related clusters, [Tp*MFe3S3X]n-, where M = Mo or W, the bridging ligand X = CR, N, NR, S, and Tp* = tris(3,5-dimethyl-1-pyrazolyl)hydroborate, to study the effects of the identity of the heterometal and the bridging X group on structure and electrochemistry. While the nature of M results in minor changes, the μ3-bridging ligand X has a large impact on reduction potentials, with differences higher than 1 V, even for the same formal charge, the most reducing clusters being supported by the carbyne ligand.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cluster Models of FeMoco with Sulfide and Carbyne Ligands: Effect of Interstitial Atom in Nitrogenase Active Site

Le¹,

Bailey²,

Scott³

et al. 2021

Preprint

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“…Note, however, there are still open questions regarding the N 2 fixation mechanism, such as (i) the sequence of proton/electron transfers on the N 2 unit, (ii) when ammonia release occurs (distal and alternating mechanistic pathways [ 59 ]) and (iii) if and how the molybdenum center [ 60 ] and the central carbide [ 61 ] influence the reactivity of the FeMo-co for N 2 binding and reduction. This is a likely role of the central carbide in stabilizing the complex and coordinating the diazene or ethyne intermediate.…”

Section: Bioinspired Approachesmentioning

confidence: 99%

Comparing Molecular Mechanisms in Solar NH3 Production and Relations with CO2 Reduction

Mallamace

Papanikolaou

Perathoner

et al. 2020

IJMS

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Molecular mechanisms for N2 fixation (solar NH3) and CO2 conversion to C2+ products in enzymatic conversion (nitrogenase), electrocatalysis, metal complexes and plasma catalysis are analyzed and compared. It is evidenced that differently from what is present in thermal and plasma catalysis, the electrocatalytic path requires not only the direct coordination and hydrogenation of undissociated N2 molecules, but it is necessary to realize features present in the nitrogenase mechanism. There is the need for (i) a multi-electron and -proton simultaneous transfer, not as sequential steps, (ii) forming bridging metal hydride species, (iii) generating intermediates stabilized by bridging multiple metal atoms and (iv) the capability of the same sites to be effective both in N2 fixation and in COx reduction to C2+ products. Only iron oxide/hydroxide stabilized at defective sites of nanocarbons was found to have these features. This comparison of the molecular mechanisms in solar NH3 production and CO2 reduction is proposed to be a source of inspiration to develop the next generation electrocatalysts to address the challenging transition to future sustainable energy and chemistry beyond fossil fuels.

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“…Note, however, that there are still open questions regarding the N2 fixation mechanism, such as (i) the sequence of proton/electron transfers on the N2 unit, (ii) when ammonia release occurs (distal and alternating mechanistic pathways [59]), and (iii) if and how the molybdenum center [60] and the central carbide [61] influence the reactivity of the FeMo-co for N2 binding and reduction. This in addition to a likely role of the central carbide in stabilizing the complex and coordinate the diazene or ethyne intermediate.…”

Section: Bioinspired Approachesmentioning

confidence: 99%

Comparing Molecular Mechanisms in Solar NH3 Production and Relations with CO2 Reduction

Mallamace

Papanikolaou

Perathoner

et al. 2020

Preprint

View full text Add to dashboard Cite

Molecular mechanisms for N2 fixation (solar NH3) and CO2 conversion to C2+ products in enzymatic conversion (Nitrogenase), electrocatalysis, metal-complexes and plasma-catalysis are analysed and compared. It is evidenced that differently from what present in thermal and plasma-catalysis, the electrocatalysis path requires not only the direct coordination and hydrogenation of undissociated N2 molecule, but to realize a series of features present in the Nitrogenase mechanism. There is the need of i) a multi-electron and -proton simultaneous transfer, not as sequential steps, ii) forming bridging metal hydride species, iii) generate intermediates stabilized by bridging multiple metal atoms, iv) have the capability of the same sites to be effective both in N2 fixation and in COx reduction to C2+ products. Only iron oxide/hydroxide stabilized at defective sites of nanocarbons was found to have these features. This comparison of the molecular mechanisms in solar NH3 production and relations with CO2 reduction is proposed to be a source of inspiration to develop the next generation electrocatalysts to address the challenging transition to a future sustainable energy and chemistry beyond fossil fuels.

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The influences of carbon donor ligands on biomimetic multi-iron complexes for N₂reduction

Abstract: High-spin diiron alkylidenes give insight into the electronic structure and functional relevance of carbon in the FeMoco active site of nitrogenase.

Cited by 26 publications

References 84 publications

Cluster Models of FeMoco with Sulfide and Carbyne Ligands: Effect of Interstitial Atom in Nitrogenase Active Site

Cluster Models of FeMoco with Sulfide and Carbyne Ligands: Effect of Interstitial Atom in Nitrogenase Active Site

Comparing Molecular Mechanisms in Solar NH3 Production and Relations with CO2 Reduction

Comparing Molecular Mechanisms in Solar NH<sub>3</sub> Production and Relations with CO<sub>2</sub> Reduction

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