1
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Agarwal T, Kaur‐Ghumaan S. [FeFe] Hydrogenase: 2‐Propanethiolato‐Bridged {FeFe} Systems as Electrocatalysts for Hydrogen Production in Acetonitrile‐Water. Eur J Inorg Chem 2023. [DOI: 10.1002/ejic.202200623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- Tashika Agarwal
- Department of Chemistry University of Delhi Delhi 110007 India
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2
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Bai SF, Du X, Tian WJ, Xu H, Zhang RF, Ma C, Wang Y, Lü S, Li Q, Li YL. Di-, tri- and tetraphosphine-substituted Fe/Se carbonyls: Synthesis, Characterization and electrochemical properties. Dalton Trans 2022; 51:11125-11134. [DOI: 10.1039/d2dt01376b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The active sites of [FeFe]-hydrogenase promoted by Fe/E (E=S, Se) clusters have attracted considerable interest due to their significance for understanding the interconversion of hydrogen with protons and electrons. As...
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3
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Hogarth G, Orton G, Ghosh S, Sarker JC, Pugh D, Richmond MG, Hartl F, Alker L. Biomimetics of [FeFe]-hydrogenases incorporating redox-active ligands: Synthesis, redox and spectroelectrochemistry of diiron-dithiolate complexes with ferrocenyl-diphosphines as Fe4S4 surrogates. Dalton Trans 2022; 51:9748-9769. [DOI: 10.1039/d2dt00419d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
[FeFe]-ase biomimics containing a redox-active ferrocenyl diphosphine have been prepared and their ability to reduce protons and oxidise H2 studied, including 1,1’-bis(diphenylphosphino)ferrocene (dppf) complexes Fe2(CO)4(-dppf)(-S(CH2)nS) (n = 2, edt; n...
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4
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Isegawa M, Matsumoto T, Ogo S. Hydrogen evolution, electron-transfer, and hydride-transfer reactions in a nickel-iron hydrogenase model complex: a theoretical study of the distinctive reactivities for the conformational isomers of nickel-iron hydride. Dalton Trans 2021; 51:312-323. [PMID: 34897337 DOI: 10.1039/d1dt03582g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen fuel is a promising alternative to fossil fuel. Therefore, efficient hydrogen production is crucial to elucidate the distinctive reactivities of metal hydride species, the intermediates formed during hydrogen activation/evolution in the presence of organometallic catalysts. This study uses density functional theory (DFT) to investigate the isomerizations and reactivities of three nickel-iron (NiFe) hydride isomers synthesized by mimicking the active center of NiFe hydrogenase. Hydride transfer within these complexes, rather than a chemical reaction between the complexes, converts the three hydrides internally. Their reactivities, including their electron-transfer, hydride-transfer and proton-transfer reactions, are investigated. The bridging hydride complex exhibits a higher energy level for the highest occupied molecular orbital (HOMO) than the terminal hydride during the electron-transfer reaction. This energy level indicates that the bridging hydride is more easily oxidized and is more susceptible to electron transfer than the terminal hydride. Regarding the hydride-transfer reaction between the NiFe hydride complex and methylene blue, the terminal hydrides exhibit larger hydricity and lower reaction barriers than the bridging hydride complexes. The results of energy decomposition analysis indicate that the structural deformation energy of the terminal hydride in the transition state is smaller than that of the bridging hydride complex, which lowers the reaction barrier of hydride transfer in the terminal hydride. To produce hydrogen, the rate-determining step is represented by the protonation of the hydride, and the terminal hydrides are thermodynamically and kinetically superior to the bridging ones. The differences in the reactivities of the hydride isomers ensure the precise control of hydrogen, and the theoretical calculations can be applied to design catalysts for hydrogen activation/production.
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Affiliation(s)
- Miho Isegawa
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Takahiro Matsumoto
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Seiji Ogo
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.
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5
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Abstract
The role of deuterium in disentangling key steps of the mechanisms of H2 activation by mimics of hydrogenases is presented. These studies have allowed to a better understanding of the mode of action of the natural enzymes and their mimics.
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Affiliation(s)
- Mar Gómez-Gallego
- Departamento de Química Orgánica I and Center for Innovation in Advanced Chemistry (ORFEO-CINQA). Facultad de Química
- Universidad Complutense
- 28040-Madrid
- Spain
| | - Miguel A. Sierra
- Departamento de Química Orgánica I and Center for Innovation in Advanced Chemistry (ORFEO-CINQA). Facultad de Química
- Universidad Complutense
- 28040-Madrid
- Spain
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6
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Kleinhaus JT, Wittkamp F, Yadav S, Siegmund D, Apfel UP. [FeFe]-Hydrogenases: maturation and reactivity of enzymatic systems and overview of biomimetic models. Chem Soc Rev 2021; 50:1668-1784. [DOI: 10.1039/d0cs01089h] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
[FeFe]-hydrogenases recieved increasing interest in the last decades. This review summarises important findings regarding their enzymatic reactivity as well as inorganic models applied as electro- and photochemical catalysts.
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Affiliation(s)
| | | | - Shanika Yadav
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
| | - Daniel Siegmund
- Department of Electrosynthesis
- Fraunhofer UMSICHT
- 46047 Oberhausen
- Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I
- Ruhr University Bochum
- 44801 Bochum
- Germany
- Department of Electrosynthesis
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7
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Arrigoni F, Bertini L, Breglia R, Greco C, De Gioia L, Zampella G. Catalytic H 2 evolution/oxidation in [FeFe]-hydrogenase biomimetics: account from DFT on the interplay of related issues and proposed solutions. NEW J CHEM 2020. [DOI: 10.1039/d0nj03393f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A DFT overview on selected issues regarding diiron catalysts related to [FeFe]-hydrogenase biomimetic research, with implications for both energy conversion and storage strategies.
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Affiliation(s)
- Federica Arrigoni
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
| | - Luca Bertini
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
| | - Raffaella Breglia
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
- Department of Earth and Environmental Sciences
| | - Claudio Greco
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
- Department of Earth and Environmental Sciences
| | - Luca De Gioia
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
| | - Giuseppe Zampella
- Department of Biotechnology and Biosciences
- University of Milano – Bicocca
- 20126 Milan
- Italy
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8
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9
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Mebs S, Duan J, Wittkamp F, Stripp ST, Happe T, Apfel UP, Winkler M, Haumann M. Differential Protonation at the Catalytic Six-Iron Cofactor of [FeFe]-Hydrogenases Revealed by 57Fe Nuclear Resonance X-ray Scattering and Quantum Mechanics/Molecular Mechanics Analyses. Inorg Chem 2019; 58:4000-4013. [PMID: 30802044 DOI: 10.1021/acs.inorgchem.9b00100] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[FeFe]-hydrogenases are efficient biological hydrogen conversion catalysts and blueprints for technological fuel production. The relations between substrate interactions and electron/proton transfer events at their unique six-iron cofactor (H-cluster) need to be elucidated. The H-cluster comprises a four-iron cluster, [4Fe4S], linked to a diiron complex, [FeFe]. We combined 57Fe-specific X-ray nuclear resonance scattering experiments (NFS, nuclear forward scattering; NRVS, nuclear resonance vibrational spectroscopy) with quantum-mechanics/molecular-mechanics computations to study the [FeFe]-hydrogenase HYDA1 from a green alga. Selective 57Fe labeling at only [4Fe4S] or [FeFe], or at both subcomplexes was achieved by protein expression with a 57Fe salt and in vitro maturation with a synthetic diiron site precursor containing 57Fe. H-cluster states were populated under infrared spectroscopy control. NRVS spectral analyses facilitated assignment of the vibrational modes of the cofactor species. This approach revealed the H-cluster structure of the oxidized state (Hox) with a bridging carbon monoxide at [FeFe] and ligand rearrangement in the CO-inhibited state (Hox-CO). Protonation at a cysteine ligand of [4Fe4S] in the oxidized state occurring at low pH (HoxH) was indicated, in contrast to bridging hydride binding at [FeFe] in a one-electron reduced state (Hred). These findings are direct evidence for differential protonation either at the four-iron or diiron subcomplex of the H-cluster. NFS time-traces provided Mössbauer parameters such as the quadrupole splitting energy, which differ among cofactor states, thereby supporting selective protonation at either subcomplex. In combination with data for reduced states showing similar [4Fe4S] protonation as HoxH without (Hred') or with (Hhyd) a terminal hydride at [FeFe], our results imply that coordination geometry dynamics at the diiron site and proton-coupled electron transfer to either the four-iron or the diiron subcomplex discriminate catalytic and regulatory functions of [FeFe]-hydrogenases. We support a reaction cycle avoiding diiron site geometry changes during rapid H2 turnover.
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Affiliation(s)
| | | | | | | | | | - Ulf-Peter Apfel
- Fraunhofer UMSICHT , Osterfelder Straße 3 , 46047 Oberhausen , Germany
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10
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Kagalwala HN, Lalaoui N, Li QL, Liu L, Woods T, Rauchfuss TB. Redox and "Antioxidant" Properties of Fe 2(μ-SH) 2(CO) 4(PPh 3) 2. Inorg Chem 2019; 58:2761-2769. [PMID: 30724559 DOI: 10.1021/acs.inorgchem.8b03344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The chemistry of Fe2(μ-SH)2(CO)4(PPh3)2 (2HH) is described with attention to S-S coupling reactions. Produced by the reduction of Fe2(μ-S2)(CO)4(PPh3)2 (2), 2HH is an analogue of Fe2(μ-SH)2(CO)6 (1HH), which exhibits well-behaved S-centered redox. Both 2HH and the related 2MeH exist as isomers that differ with respect to the stereochemistry of the μ-SR ligands (R = H, Me). Compounds 2HH, 2MeH, and 2 protonate to give rare examples of Fe-SH and Fe-S2 hydrides. Salts of [H2]+, [H2HH]+, and [H2MeH]+ were characterized crystallographically. Complex 2HH reduces O2, H2O2, (PhCO2)2, and Ph2N2, giving 2. Related reactions involving 1HH gave uncharacterizable polymers. The differing behaviors of 2HH and 1HH reflect stabilization of the ferrous intermediates by the PPh3 ligands. When independently generated by the reaction of 2HH with 2,2,6,6-tetramethyl-1-piperidinyloxy, 2* quantitatively converts to 2 or, in the presence of C2H4, is trapped as the ethanedithiolate Fe2(μ-S2C2H4)(CO)4(PPh3)2. Evidence is presented that the Hieber-Gruber synthesis of 1 involves polysulfido intermediates [Fe2(μ-S n)2(CO)6]2- ( n > 1). Two relevant experiments are as follows: (i) protonation of [Fe4(μ-S)2(μ-S2)CO)12]2- gives 1 and 1HH, and (ii) oxidation of 1HH by sulfur gives 1.
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Affiliation(s)
- Husain N Kagalwala
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Noémie Lalaoui
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Qian-Li Li
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Liang Liu
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Toby Woods
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences , University of Illinois , Urbana , Illinois 61801 , United States
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11
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Pullen S, Maji S, Stein M, Ott S. Restricted rotation of an Fe(CO)2(PL3)-subunit in [FeFe]-hydrogenase active site mimics by intramolecular ligation. Dalton Trans 2019; 48:5933-5939. [DOI: 10.1039/c8dt05148h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Terminal ligand fixation by covalent linkage to the bridging bdt ligand hinders ligand rotations.
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Affiliation(s)
- Sonja Pullen
- Department of Chemistry
- Ångström Laboratory
- Uppsala University
- 75120 Uppsala
- Sweden
| | - Somnath Maji
- Department of Chemistry
- Ångström Laboratory
- Uppsala University
- 75120 Uppsala
- Sweden
| | - Matthias Stein
- Max Planck Institute for Dynamics of Complex Technical Systems
- 39106 Magdeburg
- Germany
| | - Sascha Ott
- Department of Chemistry
- Ångström Laboratory
- Uppsala University
- 75120 Uppsala
- Sweden
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12
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Zhao Y, Yu X, Hu H, Hu X, Raje S, Angamuthu R, Tung CH, Wang W. Synthetic [FeFe]-H2ase models bearing phosphino thioether chelating ligands. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2018.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Yu X, Pang M, Zhang S, Hu X, Tung CH, Wang W. Terminal Thiolate-Dominated H/D Exchanges and H2 Release: Diiron Thiol–Hydride. J Am Chem Soc 2018; 140:11454-11463. [DOI: 10.1021/jacs.8b06996] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xin Yu
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Maofu Pang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Shengnan Zhang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Xinlong Hu
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Chen-Ho Tung
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Wenguang Wang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
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14
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Pandey IK, Natarajan M, Faujdar H, Hussain F, Stein M, Kaur-Ghumaan S. Intramolecular stabilization of a catalytic [FeFe]-hydrogenase mimic investigated by experiment and theory. Dalton Trans 2018; 47:4941-4949. [PMID: 29553150 DOI: 10.1039/c7dt04837h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The mono-substituted complex [Fe2(CO)5(μ-naphthalene-2-thiolate)2(P(PhOMe-p)3)] was prepared taking after the structural principles from both [NiFe] and [FeFe]-hydrogenase enzymes. Crystal structures are reported for this complex and the all carbonyl analogue. The bridging naphthalene thiolates resemble μ-bridging cysteine amino acids. One of the naphthyl moieties forms π-π stacking interactions with the terminal bulky phosphine ligand in the crystal structure and in calculations. This interaction stabilizes the reduced and protonated forms during electrocatalytic proton reduction in the presence of acetic acid and hinders the rotation of the phosphine ligand. The intramolecular π-π stabilization, the electrochemistry and the mechanism of the hydrogen evolution reaction were investigated using computational approaches.
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Affiliation(s)
| | - Mookan Natarajan
- Department of Chemistry, University of Delhi, Delhi 110007, India.
| | - Hemlata Faujdar
- Department of Chemistry, University of Delhi, Delhi 110007, India.
| | - Firasat Hussain
- Department of Chemistry, University of Delhi, Delhi 110007, India.
| | - Matthias Stein
- Max-Planck-Institute for Dynamics of Complex Technical Systems, Molecular Simulations and Design Group, Sandtorstrasse 1, 39106 Magdeburg, Germany.
| | - Sandeep Kaur-Ghumaan
- Department of Chemistry, University of Delhi, Delhi 110007, India. and Max-Planck-Institute for Dynamics of Complex Technical Systems, Molecular Simulations and Design Group, Sandtorstrasse 1, 39106 Magdeburg, Germany.
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15
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Rumpel S, Sommer C, Reijerse E, Farès C, Lubitz W. Direct Detection of the Terminal Hydride Intermediate in [FeFe] Hydrogenase by NMR Spectroscopy. J Am Chem Soc 2018. [PMID: 29521088 DOI: 10.1021/jacs.8b00459] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hydride state intermediates are known to occur in various hydrogen conversion enzymes, including the highly efficient [FeFe] hydrogenases. The intermediate state involving a terminal iron-bound hydride has been recognized as crucial for the catalytic mechanism, but its occurrence has up to now eluded unequivocal proof under (near) physiological conditions. Here we show that the terminal hydride in the [FeFe] hydrogenase from Chlamydomonas reinhardtii can be directly detected using solution 1H NMR spectroscopy at room temperature, opening new avenues for detailed in situ investigations under catalytic conditions.
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Affiliation(s)
- Sigrun Rumpel
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Constanze Sommer
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Edward Reijerse
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Christophe Farès
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm Platz 1 , 45470 Mülheim an der Ruhr , Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
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16
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Carlson MR, Gray DL, Richers CP, Wang W, Zhao PH, Rauchfuss TB, Pelmenschikov V, Pham CC, Gee LB, Wang H, Cramer SP. Sterically Stabilized Terminal Hydride of a Diiron Dithiolate. Inorg Chem 2018; 57:1988-2001. [PMID: 29384371 DOI: 10.1021/acs.inorgchem.7b02903] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The kinetically robust hydride [t-HFe2(Me2pdt)(CO)2(dppv)2]+ ([t-H1]+) (Me2pdt2- = Me2C(CH2S-)2; dppv = cis-1,2-C2H2(PPh2)2) and related derivatives were prepared with 57Fe enrichment for characterization by NMR, FT-IR, and NRVS. The experimental results were rationalized using DFT molecular modeling and spectral simulations. The spectroscopic analysis was aimed at supporting assignments of Fe-H vibrational spectra as they relate to recent measurements on [FeFe]-hydrogenase enzymes. The combination of bulky Me2pdt2- and dppv ligands stabilizes the terminal hydride with respect to its isomerization to the 5-16 kcal/mol more stable bridging hydride ([μ-H1]+) with t1/2(313.3 K) = 19.3 min. In agreement with the nOe experiments, the calculations predict that one methyl group in [t-H1]+ interacts with the hydride with a computed CH···HFe distance of 1.7 Å. Although [t-H571]+ exhibits multiple NRVS features in the 720-800 cm-1 region containing the bending Fe-H modes, the deuterated [t-D571]+ sample exhibits a unique Fe-D/CO band at ∼600 cm-1. In contrast, the NRVS spectra for [μ-H571]+ exhibit weaker bands near 670-700 cm-1 produced by the Fe-H-Fe wagging modes coupled to Me2pdt2- and dppv motions.
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Affiliation(s)
- Michaela R Carlson
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - Danielle L Gray
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - Casseday P Richers
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - Wenguang Wang
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - Pei-Hua Zhao
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | | | - Cindy C Pham
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Leland B Gee
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Hongxin Wang
- Department of Chemistry, University of California , Davis, California 95616, United States
| | - Stephen P Cramer
- Department of Chemistry, University of California , Davis, California 95616, United States
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17
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Arrigoni F, Bertini L, De Gioia L, Cingolani A, Mazzoni R, Zanotti V, Zampella G. Mechanistic Insight into Electrocatalytic H 2 Production by [Fe 2(CN){μ-CN(Me) 2}(μ-CO)(CO)(Cp) 2]: Effects of Dithiolate Replacement in [FeFe] Hydrogenase Models. Inorg Chem 2017; 56:13852-13864. [PMID: 29112805 DOI: 10.1021/acs.inorgchem.7b01954] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DFT has been used to investigate viable mechanisms of the hydrogen evolution reaction (HER) electrocatalyzed by [Fe2(CN){μ-CN(Me)2}(μ-CO)(CO)(Cp)2] (1) in AcOH. Molecular details underlying the proposed ECEC electrochemical sequence have been studied, and the key functionalities of CN- and amino-carbyne ligands have been elucidated. After the first reduction, CN- works as a relay for the first proton from AcOH to the carbyne, with this ligand serving as the main electron acceptor for both reduction steps. After the second reduction, a second protonation occurs at CN- that forms a Fe(CNH) moiety: i.e., the acidic source for the H2 generation. The hydride (formally 2e/H+), necessary to the heterocoupling with H+ is thus provided by the μ-CN(Me)2 ligand and not by Fe centers, as occurs in typical L6Fe2S2 derivatives modeling the hydrogenase active site. It is remarkable, in this regard, that CN- plays a role more subtle than that previously expected (increasing electron density at Fe atoms). In addition, the role of AcOH in shuttling protons from CN- to CN(Me)2 is highlighted. The incompetence for the HER of the related species [Fe2{μ-CN(Me)2}(μ-CO)(CO)2(Cp)2]+ (2+) has been investigated and attributed to the loss of proton responsiveness caused by CN- replacement with CO. In the context of hydrogenase mimicry, an implication of this study is that the dithiolate strap, normally present in all synthetic models, can be removed from the Fe2 core without loss of HER, but the redox and acid-base processes underlying turnover switch from a metal-based to a ligand-based chemistry. The versatile nature of the carbyne, once incorporated in the Fe2 scaffold, could be exploited to develop more active and robust catalysts for the HER.
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Affiliation(s)
- Federica Arrigoni
- Department of Biotechnology and Biosciences, University of Milan-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca Bertini
- Department of Biotechnology and Biosciences, University of Milan-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
| | - Luca De Gioia
- Department of Biotechnology and Biosciences, University of Milan-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
| | - Andrea Cingolani
- Department of Chimica Industriale "Toso Montanari", University of Bologna , V. le Risorgimento 4, 40136 Bologna, Italy
| | - Rita Mazzoni
- Department of Chimica Industriale "Toso Montanari", University of Bologna , V. le Risorgimento 4, 40136 Bologna, Italy
| | - Valerio Zanotti
- Department of Chimica Industriale "Toso Montanari", University of Bologna , V. le Risorgimento 4, 40136 Bologna, Italy
| | - Giuseppe Zampella
- Department of Biotechnology and Biosciences, University of Milan-Bicocca , Piazza della Scienza 2, 20126 Milan, Italy
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18
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Sensi M, Baffert C, Fradale L, Gauquelin C, Soucaille P, Meynial-Salles I, Bottin H, de Gioia L, Bruschi M, Fourmond V, Léger C, Bertini L. Photoinhibition of FeFe Hydrogenase. ACS Catal 2017. [DOI: 10.1021/acscatal.7b02252] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Matteo Sensi
- Aix Marseille University, CNRS, BIP UMR 7281, 13402 CEDEX 20 Marseille, France
- Department
of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
| | - Carole Baffert
- Aix Marseille University, CNRS, BIP UMR 7281, 13402 CEDEX 20 Marseille, France
| | - Laura Fradale
- Aix Marseille University, CNRS, BIP UMR 7281, 13402 CEDEX 20 Marseille, France
| | - Charles Gauquelin
- Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792,135
CNRS:UMR 5504, Avenue
de Rangueil, 31077 Toulouse, France
| | - Philippe Soucaille
- Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792,135
CNRS:UMR 5504, Avenue
de Rangueil, 31077 Toulouse, France
| | - Isabelle Meynial-Salles
- Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792,135
CNRS:UMR 5504, Avenue
de Rangueil, 31077 Toulouse, France
| | - Hervé Bottin
- Institut
de Biologie Intégrative de la Cellule (I2BC), Institut Frédéric
Joliot, CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, F-91198 CEDEX Gif-Sur-Yvette, France
| | - Luca de Gioia
- Department
of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
| | - Maurizio Bruschi
- Department
of Earth and Environmental Sciences, Milano-Bicocca University, Piazza della
Scienza 1, 20126 Milan, Italy
- Department
of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
| | - Vincent Fourmond
- Aix Marseille University, CNRS, BIP UMR 7281, 13402 CEDEX 20 Marseille, France
| | - Christophe Léger
- Aix Marseille University, CNRS, BIP UMR 7281, 13402 CEDEX 20 Marseille, France
| | - Luca Bertini
- Department
of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza
della Scienza 2, 20126 Milan, Italy
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19
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Kositzki R, Mebs S, Schuth N, Leidel N, Schwartz L, Karnahl M, Wittkamp F, Daunke D, Grohmann A, Apfel UP, Gloaguen F, Ott S, Haumann M. Electronic and molecular structure relations in diiron compounds mimicking the [FeFe]-hydrogenase active site studied by X-ray spectroscopy and quantum chemistry. Dalton Trans 2017; 46:12544-12557. [PMID: 28905949 DOI: 10.1039/c7dt02720f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Synthetic diiron compounds of the general formula Fe2(μ-S2R)(CO)n(L)6-n (R = alkyl or aromatic groups; L = CN- or phosphines) are versatile models for the active-site cofactor of hydrogen turnover in [FeFe]-hydrogenases. A series of 18 diiron compounds, containing mostly a dithiolate bridge and terminal ligands of increasing complexity, was characterized by X-ray absorption and emission spectroscopy in combination with density functional theory. Fe K-edge absorption and Kβ main-line emission spectra revealed the varying geometry and the low-spin state of the Fe(i) centers. Good agreement between experimental and calculated core-to-valence-excitation absorption and radiative valence-to-core-decay emission spectra revealed correlations between spectroscopic and structural features and provided access to the electronic configuration. Four main effects on the diiron core were identified, which were preferentially related to variation either of the dithiolate or of the terminal ligands. Alteration of the dithiolate bridge affected mainly the Fe-Fe bond strength, while more potent donor substitution and ligand field asymmetrization changed the metal charge and valence level localization. In contrast, cyanide ligation altered all relevant properties and, in particular, the frontier molecular orbital energies of the diiron core. Mutual benchmarking of experimental and theoretical parameters provides guidelines to verify the electronic properties of related diiron compounds.
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Affiliation(s)
- Ramona Kositzki
- Freie Universität Berlin, Fachbereich Physik, 14195 Berlin, Germany.
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20
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Ringenberg MR, Wittkamp F, Apfel UP, Kaim W. Redox Induced Configurational Isomerization of Bisphosphine–Tricarbonyliron(I) Complexes and the Difference a Ferrocene Makes. Inorg Chem 2017; 56:7501-7511. [DOI: 10.1021/acs.inorgchem.7b00957] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mark R. Ringenberg
- Universität Stuttgart, Institut für Anorganische Chemie, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Florian Wittkamp
- Inorganic
Chemistry 1/Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstrasse
150, D-44780 Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic
Chemistry 1/Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstrasse
150, D-44780 Bochum, Germany
| | - Wolfgang Kaim
- Universität Stuttgart, Institut für Anorganische Chemie, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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21
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Yu X, Tung CH, Wang W, Huynh MT, Gray DL, Hammes-Schiffer S, Rauchfuss TB. Interplay between Terminal and Bridging Diiron Hydrides in Neutral and Oxidized States. Organometallics 2017; 36:2245-2253. [PMID: 28781408 DOI: 10.1021/acs.organomet.7b00297] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This study describes the structural, spectroscopic, and electrochemical properties of electronically unsymmetrical diiron hydrides. The terminal hydride Cp*Fe(pdt)Fe(dppe)(CO)H ([1(t-H)]0, Cp*- = Me5C5-, pdt2- = CH2(CH2S-)2, dppe = Ph2PC2H4PPh2) was prepared by hydride reduction of [Cp*Fe(pdt)Fe(dppe)(CO)(NCMe)]+. As established by X-ray crystallography, [1(t-H)]0 features a terminal hydride ligand. Unlike previous examples of terminal diiron hydrides, [1(t-H)]0 does not isomerize to the bridging hydride [1(μ-H)]0. Oxidation of [1(t-H)]0 gives [1(t-H)]+, which was also characterized crystallographically as its BF4- salt. Density functional theory (DFT) calculations indicate that [1(t-H)]+ is best described as containing an Cp*FeIII center. In solution, [1(t-H)]+ isomerizes to [1(μ-H)]+, as anticipated by DFT. Reduction of [1(μ-H)]+ by Cp2Co afforded the diferrous bridging hydride [1(μ-H)]0. Electrochemical measurements and DFT calculations indicate that the couples [1(t-H)]+/0 and [1(μ-H)]+/0 differ by 210 mV. Qualitative measurements indicate that [1(t-H)]0 and [1(μ-H)]0 are close in free energy. Protonation of [1(t-H)]0 in MeCN solution affords H2 even with weak acids via hydride transfer. In contrast, protonation of [1(μ-H)]0 yields 0.5 equiv of H2 by a proposed protonation-induced electron transfer process. Isotopic labeling indicates that μ-H/D ligands are inert.
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Affiliation(s)
- Xin Yu
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, People's Republic of China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, People's Republic of China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, 27 South Shanda Road, Jinan, Shandong 250100, People's Republic of China
| | - Mioy T Huynh
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Danielle L Gray
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Sharon Hammes-Schiffer
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Thomas B Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Goodwin Avenue, Urbana, Illinois 61801, United States
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22
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Eckert PA, Kubarych KJ. Dynamic Flexibility of Hydrogenase Active Site Models Studied with 2D-IR Spectroscopy. J Phys Chem A 2017; 121:608-615. [PMID: 28032999 DOI: 10.1021/acs.jpca.6b11962] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hydrogenase enzymes enable organisms to use H2 as an energy source, having evolved extremely efficient biological catalysts for the reversible oxidation of molecular hydrogen. Small-molecule mimics of these enzymes provide both simplified models of the catalysis reactions and potential artificial catalysts that might be used to facilitate a hydrogen economy. We have studied two diiron hydrogenase mimics, μ-pdt-[Fe(CO)3]2 and μ-edt-[Fe(CO)3]2 (pdt = propanedithiolate, edt = ethanedithiolate), in a series of alkane solvents and have observed significant ultrafast spectral dynamics using two-dimensional infrared (2D-IR) spectroscopy. Since solvent fluctuations in nonpolar alkanes do not lead to substantial electrostatic modulations in a solute's vibrational mode frequencies, we attribute the spectral diffusion dynamics to intramolecular flexibility. The intramolecular origin is supported by the absence of any measurable solvent viscosity dependence, indicating that the frequency fluctuations are not coupled to the solvent motional dynamics. Quantum chemical calculations reveal a pronounced coupling between the low-frequency torsional rotation of the carbonyl ligands and the terminal CO stretching vibrations. The flexibility of the CO ligands has been proposed to play a central role in the catalytic reaction mechanism, and our results highlight that the CO ligands are highly flexible on a picosecond time scale.
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Affiliation(s)
- Peter A Eckert
- Department of Chemistry, University of Michigan , 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Kevin J Kubarych
- Department of Chemistry, University of Michigan , 930 N. University Ave., Ann Arbor, Michigan 48109, United States
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23
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Schilter D, Camara JM, Huynh MT, Hammes-Schiffer S, Rauchfuss TB. Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides. Chem Rev 2016; 116:8693-749. [PMID: 27353631 PMCID: PMC5026416 DOI: 10.1021/acs.chemrev.6b00180] [Citation(s) in RCA: 397] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogenase enzymes efficiently process H2 and protons at organometallic FeFe, NiFe, or Fe active sites. Synthetic modeling of the many H2ase states has provided insight into H2ase structure and mechanism, as well as afforded catalysts for the H2 energy vector. Particularly important are hydride-bearing states, with synthetic hydride analogues now known for each hydrogenase class. These hydrides are typically prepared by protonation of low-valent cores. Examples of FeFe and NiFe hydrides derived from H2 have also been prepared. Such chemistry is more developed than mimicry of the redox-inactive monoFe enzyme, although functional models of the latter are now emerging. Advances in physical and theoretical characterization of H2ase enzymes and synthetic models have proven key to the study of hydrides in particular, and will guide modeling efforts toward more robust and active species optimized for practical applications.
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Affiliation(s)
- David Schilter
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - James M. Camara
- Department of Chemistry, Yeshiva University, 500 West 185th Street, New York, New York 10033, United States
| | - Mioy T. Huynh
- Department of Chemistry, University of Illinois at Urbana–Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Sharon Hammes-Schiffer
- Department of Chemistry, University of Illinois at Urbana–Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Thomas B. Rauchfuss
- Department of Chemistry, University of Illinois at Urbana–Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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24
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Stepwise isotope editing of [FeFe]-hydrogenases exposes cofactor dynamics. Proc Natl Acad Sci U S A 2016; 113:8454-9. [PMID: 27432985 DOI: 10.1073/pnas.1606178113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The six-iron cofactor of [FeFe]-hydrogenases (H-cluster) is the most efficient H2-forming catalyst in nature. It comprises a diiron active site with three carbon monoxide (CO) and two cyanide (CN(-)) ligands in the active oxidized state (Hox) and one additional CO ligand in the inhibited state (Hox-CO). The diatomic ligands are sensitive reporter groups for structural changes of the cofactor. Their vibrational dynamics were monitored by real-time attenuated total reflection Fourier-transform infrared spectroscopy. Combination of (13)CO gas exposure, blue or red light irradiation, and controlled hydration of three different [FeFe]-hydrogenase proteins produced 8 Hox and 16 Hox-CO species with all possible isotopic exchange patterns. Extensive density functional theory calculations revealed the vibrational mode couplings of the carbonyl ligands and uniquely assigned each infrared spectrum to a specific labeling pattern. For Hox-CO, agreement between experimental and calculated infrared frequencies improved by up to one order of magnitude for an apical CN(-) at the distal iron ion of the cofactor as opposed to an apical CO. For Hox, two equally probable isomers with partially rotated ligands were suggested. Interconversion between these structures implies dynamic ligand reorientation at the H-cluster. Our experimental protocol for site-selective (13)CO isotope editing combined with computational species assignment opens new perspectives for characterization of functional intermediates in the catalytic cycle.
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25
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Liu YC, Chu KT, Huang YL, Hsu CH, Lee GH, Tseng MC, Chiang MH. Protonation/Reduction of Carbonyl-Rich Diiron Complexes and the Direct Observation of Triprotonated Species: Insights into the Electrocatalytic Mechanism of Hydrogen Formation. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02646] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu-Chiao Liu
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
| | - Kai-Ti Chu
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
- Molecular
Science and Technology Program, TIGP, Institute of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
- Department
of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yi-Lan Huang
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
| | - Cheng-Huey Hsu
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
| | - Gene-Hsiang Lee
- Instrumentation
Center, National Taiwan University, Taipei 106, Taiwan
| | - Mei-Chun Tseng
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
| | - Ming-Hsi Chiang
- Institute
of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
- Molecular
Science and Technology Program, TIGP, Institute of Chemistry, Academia Sinica, Nankang, Taipei 115, Taiwan
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26
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Wang F, Wen M, Feng K, Liang WJ, Li XB, Chen B, Tung CH, Wu LZ. Amphiphilic polymeric micelles as microreactors: improving the photocatalytic hydrogen production of the [FeFe]-hydrogenase mimic in water. Chem Commun (Camb) 2016; 52:457-60. [DOI: 10.1039/c5cc07499a] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An amphiphilic polymeric micelle is utilized as a microreactor to load a hydrophobic [FeFe]-hydrogenase mimic for photocatalytic hydrogen production in water.
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Affiliation(s)
- Feng Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Min Wen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Ke Feng
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Wen-Jing Liang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Xu-Bing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Bin Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- The Chinese Academy of Sciences
- Beijing 100190
- P. R. China
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27
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Schilter D, Fuller AL, Gray DL. Nickel‐Molybdenum and Nickel‐Tungsten Dithiolates: Hybrid Models for Hydrogenases and Hydrodesulfurization. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- David Schilter
- IBS Center for Multidimensional Carbon Materials, Ulsan National Institute of Science and Technology 50 UNIST‐gil, Eonyang‐eup, Ulju‐gun, Ulsan 689‐798, South Korea, http://cmcm.ibs.re.kr
- Department of Chemistry, University of Illinois at Urbana‐Champaign 505 S. Mathews Ave., Urbana, Illinois 61801, USA
| | - Amy L. Fuller
- Department of Chemistry, University of Illinois at Urbana‐Champaign 505 S. Mathews Ave., Urbana, Illinois 61801, USA
| | - Danielle L. Gray
- Department of Chemistry, University of Illinois at Urbana‐Champaign 505 S. Mathews Ave., Urbana, Illinois 61801, USA
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28
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Lee Y, Anderton KJ, Sloane FT, Ermert DM, Abboud KA, García-Serres R, Murray LJ. Reactivity of Hydride Bridges in High-Spin [3M-3(μ-H)] Clusters (M = FeII, CoII). J Am Chem Soc 2015; 137:10610-7. [PMID: 26270596 DOI: 10.1021/jacs.5b05204] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The designed [3M-3(μ-H)] clusters (M = Fe(II), Co(II)) Fe3H3L (1-H) and Co3H3L (2-H) [where L(3-) is a tris(β-diketiminate) cyclophane] were synthesized by treating the corresponding M3Br3L complexes with KBEt3H. From single-crystal X-ray analysis, the hydride ligands are sterically protected by the cyclophane ligand, and these complexes selectively react with CO2 over other unsaturated substrates (e.g., CS2, Me3SiCCH, C2H2, and CH3CN). The reaction of 1-H or 2-H with CO2 at room temperature yielded Fe3(OCHO)(H)2L (1-CO2) or Co3(OCHO)(H)2L (2-CO2), respectively, which evidence the differential reactivity of the hydride ligands within these complexes. The analogous reactions at elevated temperatures revealed a distinct difference in the reactivity pattern for 2-H as compared to 1-H; Fe3(OCHO)3L (1-3CO2) was generated from 1-H, while 2-H afforded only 2-CO2.
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Affiliation(s)
- Yousoon Lee
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Kevin J Anderton
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Forrest T Sloane
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - David M Ermert
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Khalil A Abboud
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Ricardo García-Serres
- Université Grenoble Alpes, LCBM/PMB and CEA, iRTSV/CBM/PMB and CNRS, UMR 5249, LCBM/PMB, 38000 Grenoble, France
| | - Leslie J Murray
- Center for Catalysis and Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
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29
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Li CG, Zhang GF, Zhu Y, Xue F, Shang JY, Cui MJ, Lou TJ. Synthesis of bridging hydrides of phenyl-functionalized diiron propanedithiolate complexes with 1,2-bis(diphenylphosphine)ethylene or 1,2-bis(diphenylphosphine)ethane ligands. TRANSIT METAL CHEM 2015. [DOI: 10.1007/s11243-015-9937-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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30
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Rauchfuss TB. Diiron azadithiolates as models for the [FeFe]-hydrogenase active site and paradigm for the role of the second coordination sphere. Acc Chem Res 2015; 48:2107-16. [PMID: 26079848 DOI: 10.1021/acs.accounts.5b00177] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The [FeFe] hydrogenases (H2ases) catalyze the redox reaction that interconverts protons and H2. This area of biocatalysis has attracted attention because the metal-based chemistry is unusual, and the reactions have practical implications. The active site consists of a [4Fe-4S] cluster bridged to a [Fe2(μ-dithiolate)(CN)2(CO)3](z) center (z = 1- and 2-). The dithiolate cofactor is [HN(CH2S)2](2-), called the azadithiolate ([adt(H)](2-)). Although many derivatives of Fe2(SR)2(CO)6-xLx are electrocatalysts for the hydrogen evolution reaction (HER), most operate by slow nonbiomimetic pathways. Biomimetic hydrogenogenesis is thought to involve intermediates, wherein the hydride substrate is adjacent to the amine of the adt(H), being bonded to only one Fe center. Formation of terminal hydride complexes is favored when the diiron carbonyl models contain azadithiolate. Although unstable in the free state, the adt cofactor is stable once it is affixed to the Fe2 center. It can be prepared by alkylation of Fe2(SH)2(CO)6 with formaldehyde in the presence of ammonia (to give adt(H) derivatives) or amines (to give adt(R) derivatives). Weak acids protonate Fe2(adt(R))(CO)2(PR3)4 to give terminal hydrido (term-H) complexes. In contrast, protonation of the related 1,3-propanedithiolate (pdt(2-)) complexes Fe2(pdt)(CO)2(PR3)4 requires strong acids. The amine in the azadithiolate is a kinetically fast base, relaying protons to and from the iron, which is a kinetically slow base. The crystal structure of the doubly protonated model [(term-H)Fe2(Hadt(H))(CO)2(dppv)2](2+) confirms the presence of both ammonium and terminal hydrido centers, which interact through a dihydrogen bond (dppv = cis-C2H2(PPh2)2). DFT calculations indicate that this H---H interaction is sensitive to the counterions and is strengthened upon reduction of the diiron center. For the monoprotonated models, the hydride [(term-H)Fe2(adt(H))(CO)2(dppv)2](+) exists in equilibrium with the ammonium tautomer [Fe2(Hadt(H))(CO)2(dppv)2](+). Both [(term-H)Fe2(Hadt(H))(CO)2(dppv)2](2+) and [(term-H)Fe2(adt(H))(CO)2(dppv)2](+) are highly active electrocatalysts for HER. Catalysis is initiated by reduction of the diferrous center, which induces coupling of the protic ammonium center and the hydride ligand. In contrast, the propanedithiolate [(term-H)Fe2(pdt)(CO)2(dppv)2](+) is a poor electrocatalyst for HER. Oxidation of H2 has been demonstrated, starting with models for the oxidized state ("Hox"), for example, [Fe2(adt(H))(CO)3(dppv)(PMe3)](+). Featuring a distorted Fe(II)Fe(I) center, this Hox model reacts slowly with high pressures of H2 to give [(μ-H)Fe2(adt(H))(CO)3(dppv)(PMe3)](+). Highlighting the role of the proton relay, the propanedithiolate [Fe2(pdt)(CO)3(dppv)(PMe3)](+) is unreactive toward H2. The Hox-model + H2 reaction is accelerated in the presence of ferrocenium salts, which simulate the role of the attached [4Fe-4S] cluster. The redox-complemented complex [Fe2(adt(Bn))(CO)3(dppv)(FcP*)](n+) catalyzes both proton reduction and hydrogen oxidation (FcP* = (C5Me5)Fe(C5Me4CH2PEt2)).
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Affiliation(s)
- Thomas B. Rauchfuss
- School of Chemical Sciences, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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31
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Gouré E, Carboni M, Dubourdeaux P, Clémancey M, Balasubramanian R, Lebrun C, Bayle PA, Maldivi P, Blondin G, Latour JM. Cis/trans isomerizations in diiron complexes involving aniline or anilide ligands. Inorg Chem 2014; 53:10060-9. [PMID: 25254906 DOI: 10.1021/ic501793v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recently reported a deprotonation-induced valence inversion within a phenoxido-bridged mixed-valent diiron(II,III) complex. The initial aniline coordinated to the Fe(II) site reacts with triethylamine, and the resulting complex contains an anilide ligand coordinated to the Fe(III) ion. The behavior of these complexes in acetonitrile is indeed more intricate. Owing to the very distinctive spectroscopic signatures of the complexes, the conjunction of NMR, Mössbauer, and UV-visible absorption spectroscopies allows one to evidence two isomerization reactions, one involving the aniline linked to Fe(II) and the other the anilide on Fe(III). Theoretical calculations sustain this conclusion. Aniline in the cis position versus the bridging phenoxide is shown to be the most stable isomer while the anilide trans to the phenoxido bridge is favored. The trans isomer of the aniline complex is more acidic than the cis one by 1 pKa unit. Isomerization of the anilide complex is 10 times faster than the analogous isomerization of the aniline complex. Both reactions are proposed to proceed through a unique mechanism. This is the first time that such isomerization reactions are evidenced in dinuclear complexes.
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Affiliation(s)
- Eric Gouré
- CEA, iRTSV/LCBM, pmb , F-38000 Grenoble, France
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32
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Huynh MT, Wang W, Rauchfuss TB, Hammes-Schiffer S. Computational investigation of [FeFe]-hydrogenase models: characterization of singly and doubly protonated intermediates and mechanistic insights. Inorg Chem 2014; 53:10301-11. [PMID: 25207842 PMCID: PMC4186672 DOI: 10.1021/ic5013523] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
The [FeFe]-hydrogenase enzymes catalyze
hydrogen oxidation and production efficiently with binuclear Fe metal
centers. Recently the bioinspired H2-producing model system
Fe2(adt)(CO)2(dppv)2 (adt=azadithiolate
and dppv=diphosphine) was synthesized and studied experimentally.
In this system, the azadithiolate bridge facilitates the formation
of a doubly protonated ammonium-hydride species through a proton relay.
Herein computational methods are utilized to examine this system in
the various oxidation states and protonation states along proposed
mechanistic pathways for H2 production. The calculated
results agree well with the experimental data for the geometries,
CO vibrational stretching frequencies, and reduction potentials. The
calculations illustrate that the NH···HFe dihydrogen
bonding distance in the doubly protonated species is highly sensitive
to the effects of ion-pairing between the ammonium and BF4– counterions, which are present in the crystal
structure, in that the inclusion of BF4– counterions leads to a significantly longer dihydrogen bond. The
non-hydride Fe center was found to be the site of reduction for terminal
hydride species and unsymmetric bridging hydride species, whereas
the reduced symmetric bridging hydride species exhibited spin delocalization
between the Fe centers. According to both experimental measurements
and theoretical calculations of the relative pKa values, the Fed center of the neutral species
is more basic than the amine, and the bridging hydride species is
more thermodynamically stable than the terminal hydride species. The
calculations implicate a possible pathway for H2 evolution
that involves an intermediate with H2 weakly bonded to
one Fe, a short H2 distance similar to the molecular bond
length, the spin density delocalized over the two Fe centers, and
a nearly symmetrically bridged CO ligand. Overall, this study illustrates
the mechanistic roles of the ammonium-hydride interaction, flexibility
of the bridging CO ligand, and intramolecular electron transfer between
the Fe centers in the catalytic cycle. Such insights will assist in
the design of more effective bioinspired catalysts for H2 production. Theoretical calculations
in conjunction with supporting experimental data are used to analyze
the mechanistic pathway for hydrogen evolution catalyzed by the bioinspired
model Fe2(adt)(CO)2(dppv)2. This
study elucidates the site of reduction and the pKa values associated with formation of the singly and doubly
protonated species, as well as the roles of the ammonium-hydride interaction,
flexibility of the bridging CO ligand, and intramolecular electron
transfer between the Fe centers in the catalytic cycle for H2 production.
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Affiliation(s)
- Mioy T Huynh
- Department of Chemistry, 600 South Mathews Avenue, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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33
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Frederix PWJM, Adamczyk K, Wright JA, Tuttle T, Ulijn RV, Pickett CJ, Hunt NT. Investigation of the Ultrafast Dynamics Occurring during Unsensitized Photocatalytic H2 Evolution by an [FeFe]-Hydrogenase Subsite Analogue. Organometallics 2014. [DOI: 10.1021/om500521w] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Pim W. J. M. Frederix
- Department
of Physics, University of Strathclyde, SUPA, Glasgow G4 0NG, United Kingdom
- WestCHEM,
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, United Kingdom
| | - Katrin Adamczyk
- Department
of Physics, University of Strathclyde, SUPA, Glasgow G4 0NG, United Kingdom
| | - Joseph A. Wright
- Energy
Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research
Park, Norwich NR4 7TJ, United Kingdom
| | - Tell Tuttle
- WestCHEM,
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, United Kingdom
| | - Rein V. Ulijn
- WestCHEM,
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL, United Kingdom
| | - Christopher J. Pickett
- Energy
Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research
Park, Norwich NR4 7TJ, United Kingdom
| | - Neil T. Hunt
- Department
of Physics, University of Strathclyde, SUPA, Glasgow G4 0NG, United Kingdom
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34
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Lansing JC, Camara JM, Gray DE, Rauchfuss TB. Hydrogen Production Catalyzed by Bidirectional, Biomimetic Models of the [FeFe]-Hydrogenase Active Site. Organometallics 2014; 33:5897-5906. [PMID: 25364093 PMCID: PMC4210170 DOI: 10.1021/om5004013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 12/18/2022]
Abstract
Active site mimics of [FeFe]-hydrogenase are shown to be bidirectional catalysts, producing H2 upon treatment with protons and reducing equivalents. This reactivity complements the previously reported oxidation of H2 by these same catalysts in the presence of oxidants. The complex Fe2(adtBn)(CO)3(dppv)(PFc*Et2 ) ([1]0; adtBn = (SCH2)2NBn, dppv = cis-1,2-bis(diphenylphosphino)ethylene, PFc*Et2 = Et2PCH2C5Me4FeCp*) reacts with excess [H(OEt2)2]BArF4 (BArF4- = B(C6H3-3,5-(CF3)2)4-) to give ∼0.5 equiv of H2 and [Fe2(adtBnH)(CO)3(dppv)(PFc*Et2 )]2+ ([1H]2+). The species [1H]2+ consists of a ferrocenium ligand, an N-protonated amine, and an FeIFeI core. In the presence of additional reducing equivalents in the form of decamethylferrocene (Fc*), hydrogen evolution is catalytic, albeit slow. The related catalyst Fe2(adtBn)(CO)3(dppv)(PMe3) (3) behaves similarly in the presence of Fc*, except that in the absence of excess reducing agent it converts to the catalytically inactive μ-hydride derivative [μ-H3]+. Replacement of the adt in [1]0 with propanedithiolate (pdt) results in a catalytically inactive complex. In the course of synthesizing [FeFe]-hydrogenase mimics, new routes to ferrocenylphosphine ligands and nonamethylferrocene were developed.
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Affiliation(s)
- James C Lansing
- Department of Chemistry, University of Illinois 600 S. Goodwin Avenue Urbana, Illinois 61801, United States
| | - James M Camara
- Department of Chemistry, University of Illinois 600 S. Goodwin Avenue Urbana, Illinois 61801, United States
| | - Danielle E Gray
- Department of Chemistry, University of Illinois 600 S. Goodwin Avenue Urbana, Illinois 61801, United States
| | - Thomas B Rauchfuss
- Department of Chemistry, University of Illinois 600 S. Goodwin Avenue Urbana, Illinois 61801, United States
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35
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Rahaman A, Ghosh S, Unwin DG, Basak-Modi S, Holt KB, Kabir SE, Nordlander E, Richmond MG, Hogarth G. Bioinspired Hydrogenase Models: The Mixed-Valence Triiron Complex [Fe 3(CO) 7(μ-edt) 2] and Phosphine Derivatives [Fe 3(CO) 7-x (PPh 3) x (μ-edt) 2] ( x = 1, 2) and [Fe 3(CO) 5(κ 2-diphosphine)(μ-edt) 2] as Proton Reduction Catalysts. Organometallics 2014; 33:1356-1366. [PMID: 24748710 PMCID: PMC3985925 DOI: 10.1021/om400691q] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Indexed: 01/23/2023]
Abstract
The mixed-valence triiron complexes [Fe3(CO)7-x (PPh3) x (μ-edt)2] (x = 0-2; edt = SCH2CH2S) and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist only in the dibasal form in both the solid state and solution. The carbonyl on the central iron atom is semibridging, and this leads to a rotated structure between the bridged diiron center. IR studies reveal that all complexes are inert to protonation by HBF4·Et2O, but addition of acid to the pentacarbonyl complexes results in one-electron oxidation to yield the moderately stable cations [Fe3(CO)5(PPh3)2(μ-edt)2]+ and [Fe3(CO)5(κ2-diphosphine)(μ-edt)2]+, species which also result upon oxidation by [Cp2Fe][PF6]. The electrochemistry of the formally Fe(I)-Fe(II)-Fe(I) complexes has been investigated. Each undergoes a quasi-reversible oxidation, the potential of which is sensitive to phosphine substitution, generally occurring between 0.15 and 0.50 V, although [Fe3(CO)5(PPh3)2(μ-edt)2] is oxidized at -0.05 V. Reduction of all complexes is irreversible and is again sensitive to phosphine substitution, varying between -1.47 V for [Fe3(CO)7(μ-edt)2] and around -1.7 V for phosphine-substituted complexes. In their one-electron-reduced states, all complexes are catalysts for the reduction of protons to hydrogen, the catalytic overpotential being increased upon successive phosphine substitution. In comparison to the diiron complex [Fe2(CO)6(μ-edt)], [Fe3(CO)7(μ-edt)2] catalyzes proton reduction at 0.36 V less negative potentials. Electronic structure calculations have been carried out in order to fully elucidate the nature of the oxidation and reduction processes. In all complexes, the HOMO comprises an iron-iron bonding orbital localized between the two iron atoms not ligated by the semibridging carbonyl, while the LUMO is highly delocalized in nature and is antibonding between both pairs of iron atoms but also contains an antibonding dithiolate interaction.
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Affiliation(s)
- Ahibur Rahaman
- Department of Chemistry, Jahangirnagar
University, Savar, Dhaka 1342, Bangladesh
- Inorganic Chemistry Research Group, Chemical
Physics, Center for Chemistry and Chemical Engineering, Lund University, P.O.
Box 124, SE-22100 Lund, Sweden
| | - Shishir Ghosh
- Department of Chemistry, Jahangirnagar
University, Savar, Dhaka 1342, Bangladesh
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - David G. Unwin
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Sucharita Basak-Modi
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Katherine B. Holt
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
| | - Shariff E. Kabir
- Department of Chemistry, Jahangirnagar
University, Savar, Dhaka 1342, Bangladesh
| | - Ebbe Nordlander
- Inorganic Chemistry Research Group, Chemical
Physics, Center for Chemistry and Chemical Engineering, Lund University, P.O.
Box 124, SE-22100 Lund, Sweden
| | - Michael G. Richmond
- Department of Chemistry, University of North Texas, 1155 Union Circle, Box 305070, Denton, Texas 76203, United States
| | - Graeme Hogarth
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
- Department of Chemistry, King’s College London, Britannia
House, 7 Trinity Street, London SE1 1DB, U.K.
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36
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Carroll M, Chen J, Gray DE, Lansing JC, Rauchfuss TB, Schilter D, Volkers PI, Wilson S. Ferrous Carbonyl Dithiolates as Precursors to FeFe, FeCo, and FeMn Carbonyl Dithiolates. Organometallics 2014; 33:858-867. [PMID: 24803716 PMCID: PMC3999794 DOI: 10.1021/om400752a] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Indexed: 01/23/2023]
Abstract
Reported are complexes of the formula Fe(dithiolate)(CO)2(diphos) and their use to prepare homo- and heterobimetallic dithiolato derivatives. The starting iron dithiolates were prepared by a one-pot reaction of FeCl2 and CO with chelating diphosphines and dithiolates, where dithiolate = S2(CH2)22- (edt2-), S2(CH2)32- (pdt2-), S2(CH2)2(C(CH3)2)2- (Me2pdt2-) and diphos = cis-C2H2(PPh2)2 (dppv), C2H4(PPh2)2 (dppe), C6H4(PPh2)2 (dppbz), C2H4[P(C6H11)2]2 (dcpe). The incorporation of 57Fe into such building block complexes commenced with the conversion of 57Fe into 57Fe2I4( i PrOH)4, which then was treated with K2pdt, CO, and dppe to give 57Fe(pdt)(CO)2(dppe). NMR and IR analyses show that these complexes exist as mixtures of all-cis and trans-CO isomers, edt2- favoring the former and pdt2- the latter. Treatment of Fe(dithiolate)(CO)2(diphos) with the Fe(0) reagent (benzylideneacetone)Fe(CO)3 gave Fe2(dithiolate)(CO)4(diphos), thereby defining a route from simple ferrous salts to models for hydrogenase active sites. Extending the building block route to heterobimetallic complexes, treatment of Fe(pdt)(CO)2(dppe) with [(acenaphthene)Mn(CO)3]+ gave [(CO)3Mn(pdt)Fe(CO)2(dppe)]+ ([3d(CO)]+). Reduction of [3d(CO)]+ with BH4- gave the Cs -symmetric μ-hydride (CO)3Mn(pdt)(H)Fe(CO)(dppe) (H3d). Complex H3d is reversibly protonated by strong acids, the proposed site of protonation being sulfur. Treatment of Fe(dithiolate)(CO)2(diphos) with CpCoI2(CO) followed by reduction by Cp2Co affords CpCo(dithiolate)Fe(CO)(diphos) (4), which can also be prepared from Fe(dithiolate)(CO)2(diphos) and CpCo(CO)2. Like the electronically related (CO)3Fe(pdt)Fe(CO)(diphos), these complexes undergo protonation to afford the μ-hydrido complexes [CpCo(dithiolate)HFe(CO)(diphos)]+. Low-temperature NMR studies indicate that Co is the kinetic site of protonation.
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Affiliation(s)
- Maria
E. Carroll
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Jinzhu Chen
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Danielle E. Gray
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - James C. Lansing
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Thomas B. Rauchfuss
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - David Schilter
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Phillip I. Volkers
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Scott
R. Wilson
- Department
of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
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37
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Lambertz C, Chernev P, Klingan K, Leidel N, Sigfridsson KGV, Happe T, Haumann M. Electronic and molecular structures of the active-site H-cluster in [FeFe]-hydrogenase determined by site-selective X-ray spectroscopy and quantum chemical calculations. Chem Sci 2014. [DOI: 10.1039/c3sc52703d] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Site-selective X-ray spectroscopy discriminated the cubane and diiron units in the H-cluster of [FeFe]-hydrogenase revealing its electronic and structural configurations.
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Affiliation(s)
- Camilla Lambertz
- Institute for Biochemistry of Plants
- Department of Photobiotechnology
- Ruhr-University Bochum
- 44780 Bochum, Germany
| | - Petko Chernev
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | - Katharina Klingan
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | - Nils Leidel
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
| | | | - Thomas Happe
- Institute for Biochemistry of Plants
- Department of Photobiotechnology
- Ruhr-University Bochum
- 44780 Bochum, Germany
| | - Michael Haumann
- Institute for Experimental Physics
- Freie Universität Berlin
- FB Physik
- 14195 Berlin, Germany
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38
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Teramoto Y, Kubo K, Kume S, Mizuta T. Formation of a Hexacarbonyl Diiron Complex Having a Naphthalene-1,8-bis(phenylphosphido) Bridge and the Electrochemical Behavior of Its Derivatives. Organometallics 2013. [DOI: 10.1021/om4006142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuichi Teramoto
- Department
of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan
| | - Kazuyuki Kubo
- Department
of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan
| | - Shoko Kume
- Department
of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan
| | - Tsutomu Mizuta
- Department
of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan
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39
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Yen TH, Chu KT, Chiu WW, Chien YC, Lee GH, Chiang MH. Synthesis and characterization of the diiron biomimics bearing phosphine borane for hydrogen formation. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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40
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Wang H, Liu X. Intramolecular hydrogen bonding interaction, a mechanism for the bridging linkages to exert electronic influence on diiron models of [FeFe]-hydrogenase. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Bertini L, Fantucci P, De Gioia L, Zampella G. Excited state properties of diiron dithiolate hydrides: implications in the unsensitized photocatalysis of H2 evolution. Inorg Chem 2013; 52:9826-41. [PMID: 23952259 DOI: 10.1021/ic400818t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Density functional theory (DFT) and time-dependent DFT (TDDFT) have been used to investigate how visible light photons can excite an asymmetrically substituted diiron hydride, [Fe2(pdt)(μ-H)(CO)4dppv](+) (1(+), dppv = cis-1,2-C2H2(PPh2)2; pdt = 1,3-propanedithiolate), as well as the symmetric species [Fe2(pdt)(μ-H)(CO)4(PMe3)2](+) (2(+)), which are the first photocatalysts of proton reduction operating without employing sensitizers (Wang, W.; Rauchfuss, T. B.; Bertini, L.; Zampella, G.; J. Am. Chem. Soc., 2012, 134, 4525). Theoretical results illustrate that the peculiar reactivity associated to the excited states of 1(+) and 2(+) is compatible with three different scenarios: (i) it can arise from the movement of the hydride ligand from fully bridging to semibridging/terminal coordination, which is expected to be more reactive toward protons; (ii) reactivity could be related to cleavage of a Fe-S bond, which implies formation of a transient Fe penta-coordinate species that would trigger a facile turnstile hydride isomerization, if lifetime excitation is long enough; (iii) also in line with a Fe-S bond cleavage is the possibility that after excited state decay, a highly basic S center is protonated so that a species simultaneously containing S-H(δ+) and Fe-H(δ-) moieties is formed and, once reduced by a suitable electron donor, it can readily afford H2 plus an unprotonated form of the FeFe complex. This last possibility is consistent with (31)P NMR and IR solution data. All the three possibilities are compatible with the capability of 1(+) and 2(+) to perform photocatalysis of hydrogen evolving reaction (HER) without sensitizer. Moreover, even though it turned out difficult to discriminate among the three scenarios, especially because of the lack of experimental excitation lifetimes, it is worth underscoring that all of the three pathways represent a novelty regarding diiron carbonyl photoreactivity, which is usually associated with CO loss. Results provide also a rationale to the experimental observations which showed that the simultaneous presence of donor ligands (dppv in the case of 1(+)) and a H ligand in the coordination environment of diiron complexes is a key factor to prevent CO photodissociation and catalyze HER. Finally, the comparison of photoexcitation behavior of 1(+) and 2(+) allows a sort of generalization about the functioning of such hydride species.
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Affiliation(s)
- Luca Bertini
- Department of Biotechnology and Biosciences, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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42
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Wang W, Nilges MJ, Rauchfuss TB, Stein M. Isolation of a Mixed Valence Diiron Hydride: Evidence for a Spectator Hydride in Hydrogen Evolution Catalysis. J Am Chem Soc 2013; 135:3633-9. [DOI: 10.1021/ja312458f] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Wenguang Wang
- School of Chemical Sciences, University of Illinois, Urbana, Illinois 61801, United
States
| | - Mark J. Nilges
- School of Chemical Sciences, University of Illinois, Urbana, Illinois 61801, United
States
| | - Thomas B. Rauchfuss
- School of Chemical Sciences, University of Illinois, Urbana, Illinois 61801, United
States
| | - Matthias Stein
- Max Planck Institute
for Dynamics
of Complex Technical Systems, Sandtorstraβe 1, 39106 Magdeburg,
Germany
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43
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Karnahl M, Tschierlei S, Erdem ÖF, Pullen S, Santoni MP, Reijerse EJ, Lubitz W, Ott S. Mixed-valence [Fe(I)Fe(II)] hydrogenase active site model complexes stabilized by a bidentate carborane bis-phosphine ligand. Dalton Trans 2013; 41:12468-77. [PMID: 22955116 DOI: 10.1039/c2dt31192e] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of [FeFe]-hydrogenase active site analogues, with the general formula [Fe(2)(dt)(CO)(4)(BC)] 1-3 (dt = dithiolate, pdt = propyl-1,3-dt (1), bdt = benzene-1,2-dt (2), edt = ethyl-1,2-dt (3); BC = 1,2-bisdiphenylphosphine-1,2-o-carborane), has been prepared and structurally characterized. While the electrochemical reductions of 1-3 are largely invariant to the different nature of their dt bridges, the oxidations differ by more than 120 mV in between the series. Remarkably, all three compounds are reversibly oxidized, with complex 1 that contains the most electron-donating pdt ligand at the mildest potential of -0.09 V vs. Fc/Fc(+). The one-electron oxidized state 1(ox) is stable for several minutes and was spectroscopically characterized by FTIR and EPR. EPR spectroscopy provided evidence that in the mixed-valence [Fe(I)Fe(II)] state most of the spin density is located on the iron with the BC-ligand. This is monitored through the strong (31)P hyperfine coupling of the phenyl groups of the BC ligand, while further delocalization into the o-carborane unit is negligible.
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Affiliation(s)
- Michael Karnahl
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden.
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44
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Leidel N, Hsieh CH, Chernev P, Sigfridsson KGV, Darensbourg MY, Haumann M. Bridging-hydride influence on the electronic structure of an [FeFe] hydrogenase active-site model complex revealed by XAES-DFT. Dalton Trans 2013; 42:7539-54. [DOI: 10.1039/c3dt33042g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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45
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Zaffaroni R, Rauchfuss TB, Fuller A, De Gioia L, Zampella G. Contrasting Protonation Behavior of Diphosphido vs Dithiolato Diiron(I) Carbonyl Complexes. Organometallics 2012. [DOI: 10.1021/om300997s] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Riccardo Zaffaroni
- Department
of Chemistry, University of Illinois, Urbana, Illinois
61801, United States
| | - Thomas B. Rauchfuss
- Department
of Chemistry, University of Illinois, Urbana, Illinois
61801, United States
| | - Amy Fuller
- Department
of Chemistry, University of Illinois, Urbana, Illinois
61801, United States
| | - Luca De Gioia
- Department of Biotechnology
and Biosciences, University of Milano-Bicocca, 20126-Milan, Italy
| | - Giuseppe Zampella
- Department of Biotechnology
and Biosciences, University of Milano-Bicocca, 20126-Milan, Italy
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46
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Zaffaroni R, Rauchfuss TB, Gray DL. Terminal vs bridging hydrides of diiron dithiolates: protonation of Fe2(dithiolate)(CO)2(PMe3)4. J Am Chem Soc 2012; 134:19260-9. [PMID: 23095145 PMCID: PMC3518320 DOI: 10.1021/ja3094394] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This investigation examines the protonation of diiron dithiolates, exploiting the new family of exceptionally electron-rich complexes Fe(2)(xdt)(CO)(2)(PMe(3))(4), where xdt is edt (ethanedithiolate, 1), pdt (propanedithiolate, 2), and adt (2-aza-1,3-propanedithiolate, 3), prepared by the photochemical substitution of the corresponding hexacarbonyls. Compounds 1-3 oxidize near -950 mV vs Fc(+/0). Crystallographic analyses confirm that 1 and 2 adopt C(2)-symmetric structures (Fe-Fe = 2.616 and 2.625 Å, respectively). Low-temperature protonation of 1 afforded exclusively [μ-H1](+), establishing the non-intermediacy of the terminal hydride ([t-H1](+)). At higher temperatures, protonation afforded mainly [t-H1](+). The temperature dependence of the ratio [t-H1](+)/[μ-H1](+) indicates that the barriers for the two protonation pathways differ by ∼4 kcal/mol. Low-temperature (31)P{(1)H} NMR measurements indicate that the protonation of 2 proceeds by an intermediate, proposed to be the S-protonated dithiolate [Fe(2)(Hpdt)(CO)(2)(PMe(3))(4)](+) ([S-H2](+)). This intermediate converts to [t-H2](+) and [μ-H2](+) by first-order and second-order processes, respectively. DFT calculations support transient protonation at sulfur and the proposal that the S-protonated species (e.g., [S-H2](+)) rearranges to the terminal hydride intramolecularly via a low-energy pathway. Protonation of 3 affords exclusively terminal hydrides, regardless of the acid or conditions, to give [t-H3](+), which isomerizes to [t-H3'](+), wherein all PMe(3) ligands are basal.
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Affiliation(s)
| | | | - Danielle L. Gray
- Department of Chemistry, University of Illinois Urbana, IL 61801, USA
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Carroll ME, Barton BE, Rauchfuss TB, Carroll PJ. Synthetic models for the active site of the [FeFe]-hydrogenase: catalytic proton reduction and the structure of the doubly protonated intermediate. J Am Chem Soc 2012; 134:18843-52. [PMID: 23126330 DOI: 10.1021/ja309216v] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This report compares biomimetic hydrogen evolution reaction catalysts with and without the amine cofactor (adt(NH)): Fe(2)(adt(NH))(CO)(2)(dppv)(2) (1(NH)) and Fe(2)(pdt)(CO)(2)(dppv)(2) (2) [(adt(NH))(2-) = HN(CH(2)S)(2)(2-), pdt(2-) = 1,3-(CH(2))(3)S(2)(2-), and dppv = cis-C(2)H(2)(PPh(2))(2)]. These compounds are spectroscopically, structurally, and stereodynamically very similar but exhibit very different catalytic properties. Protonation of 1(NH) and 2 gives three isomeric hydrides each, beginning with the kinetically favored terminal hydride, which converts sequentially to sym and unsym isomers of the bridging hydrides. In the case of 1(NH), the corresponding ammonium hydrides are also observed. In the case of the terminal amine hydride [t-H1(NH)]BF(4), the ammonium/amine hydride equilibrium is sensitive to counteranions and solvent. The species [t-H1(NH(2))](BF(4))(2) represents the first example of a crystallographically characterized terminal hydride produced by protonation. The NH---HFe distance of 1.88(7) Å indicates dihydrogen-bonding. The bridging hydrides [μ-H1(NH)](+) and [μ-H2](+) reduce near -1.8 V, about 150 mV more negative than the reductions of the terminal hydride [t-H1(NH)](+) and [t-H2](+) at -1.65 V. Reductions of the amine hydrides [t-H1(NH)](+) and [t-H1(NH(2))](2+) are irreversible. For the pdt analogue, the [t-H2](+/0) couple is unaffected by weak acids (pK(a)(MeCN) = 15.3) but exhibits catalysis with HBF(4)·Et(2)O, albeit with a turnover frequency (TOF) around 4 s(-1) and an overpotential greater than 1 V. The voltammetry of [t-H1(NH)](+) is strongly affected by relatively weak acids and proceeds at 5000 s(-1) with an overpotential of 0.7 V. The ammonium hydride [t-H1(NH(2))](2+) is a faster catalyst, with an estimated TOF of 58 000 s(-1) and an overpotential of 0.5 V.
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Affiliation(s)
- Maria E Carroll
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Illinois 61801, United States
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Olsen MT, Rauchfuss TB, Zaffaroni R. Reaction of Aryl Diazonium Salts and Diiron(I) Dithiolato Carbonyls: Evidence for Radical Intermediates. Organometallics 2012; 31:3447-3450. [PMID: 22962513 DOI: 10.1021/om300107s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Treatment of Fe(2)(pdt)(CO)(4)(dppv) (1) with aryldiazonium salts affords the 34e(-) adducts [Fe(2)(pdt)(μ-N(2)Ar)(CO)(4)(dppv)](+) (pdt(2-) = 1,3-propanedithiolate, dppv = cis-C(2)H(2)(PPh(2))(2)). Under some conditions, the same reaction gave substantial amounts of [1](+), the product of electron-transfer. Consistent with the influence of electron transfer in the reactions of some electrophiles with Fe(I)Fe(I) dithiolates, the reaction of [Me(3)S(2)](+) and Fe(2)(pdt)(CO)(4)(dppbz) was found to give [Fe(2)(pdt)(CO)(4)(dppbz)](+) as well as Me(2)S and Me(2)S(2) (dppbz = 1,2-bis(diphenylphosphino)benzene).
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Affiliation(s)
- Matthew T Olsen
- School of Chemical Sciences, University of Illinois, Urbana, IL 61801
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Chouffai D, Zampella G, Capon JF, De Gioia L, Gloaguen F, Pétillon FY, Schollhammer P, Talarmin J. Oxidatively Induced Reactivity of [Fe2(CO)4(κ2-dppe)(μ-pdt)]: an Electrochemical and Theoretical Study of the Structure Change and Ligand Binding Processes. Inorg Chem 2011; 50:12575-85. [DOI: 10.1021/ic201601q] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dounia Chouffai
- UMR CNRS 6521, Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, UFR Sciences et Techniques, Cs 93837, 29238 Brest-Cedex 3, France
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Jablonskytė A, Wright JA, Fairhurst SA, Peck JNT, Ibrahim SK, Oganesyan VS, Pickett CJ. Paramagnetic Bridging Hydrides of Relevance to Catalytic Hydrogen Evolution at Metallosulfur Centers. J Am Chem Soc 2011; 133:18606-9. [DOI: 10.1021/ja2087536] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aušra Jablonskytė
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Joseph A. Wright
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | | | - Jamie N. T. Peck
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Saad K. Ibrahim
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Vasily S. Oganesyan
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
| | - Christopher J. Pickett
- Energy Materials Laboratory, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
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