[Ni(NHPnPr3)(`S3')], the First Nickel Thiolate Complex Modeling the Nickel Cysteinate Site and Reactivity of [NiFe] Hydrogenase

Sellmann, Dieter; Geipel, Franz; Moll, Matthias

doi:10.1002/(sici)1521-3773(20000204)39:3<561::aid-anie561>3.0.co;2-3

Cited by 88 publications

(12 citation statements)

References 3 publications

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“…368 The product [47(μ-H)] − and its relatives are the first [NiFe]-H 2 ase models containing both CN − and H − groups. Aside from its CO occupying a basal site, the Fe coordination sphere in [47(μ-H)] − completely reproduces that in Ni-R, with the BR 3 groups simulating the H-bonding exhibited by the CN − ligands 370 Such Ni(η 2 -H 2 ) species can exhibit heterolysis with 371 and without an external base 372 (middle and bottom, respectively). This rarity had initially led to doubts about Ni performing H 2 cleavage in [NiFe]-H 2 ase, although this is now thought to be the case.…”

Section: Chemical Reviewsmentioning

confidence: 84%

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Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

et al. 2016

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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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Section: Chemical Reviewsmentioning

confidence: 84%

“…Early evidence for Ni interaction with H 2 could be found from [ 49 H], which converts to its D isotopologue [ 49 D] under D 2 (Figure ). The formation of a short-lived D 2 complex is thought to be followed by heterolysis of D 2 , with Ni receiving D – and thiolate accepting D + .…”

Section: [Nife]-h2asesmentioning

confidence: 99%

Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

et al. 2016

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“…Additionally, the HD analogue, (SiP 2 S)Ni II (HD), exhibits a 1 J HD of 35 Hz (toluene- d 8 , −80 °C), indicative of an intact dihydrogen unit in solution . Examples of Ni(H 2 ) complexes are rare, , and 7 is distinct by virtue of the thiolate donor ligand; H 2 activation across a Ni–thiolate bond has been invoked elsewhere …”

Section: Resultsmentioning

confidence: 99%

H₂ Evolution from a Thiolate-Bound Ni(III) Hydride

Oyala

Peters

2020

J. Am. Chem. Soc.

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Terminal Ni III hydrides are proposed intermediates in proton reduction catalyzed by both molecular electrocatalysts and metalloenzymes, but welldefined examples of paramagnetic nickel hydride complexes are largely limited to bridging hydrides. Herein, we report the synthesis of an S = ½, terminally bound thiolate-Ni III-H complex. This species, and its terminal hydride ligand in particular, have been thoroughly characterized by vibrational and EPR techniques, including pulse EPR studies. Corresponding DFT calculations suggest appreciable spin leakage onto the thiolate ligand. The hyperfine coupling to the terminal hydride ligand of the thiolate-Ni III-H species is comparable to that of the hydride ligand proposed for the Ni-C hydrogenase intermediate (Ni III-H-Fe II). Upon warming, the featured thiolate-Ni III-H species undergoes bimolecular reductive elimination of H2. Associated kinetic studies are discussed and compared with a structurally related Fe III-H species that has been recently reported to also undergo bimolecular H-H coupling.

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“…The H/D scrambling experiments were conducted in a J. Young tube in CD 2 Cl 2 at room temperature. − Typically, D 2 O (5 μL) was carefully injected under an N 2 atmosphere into an NMR tube containing 0.6 mL of CD 2 Cl 2 solution of [ 1 (μ-H)H] + (5.3 μmol). The solution was frozen in liquid nitrogen, evaporated, and then purged with H 2 at 15 psi.…”

Section: Resultsmentioning

confidence: 99%

Terminal Thiolate-Dominated H/D Exchanges and H₂ Release: Diiron Thiol–Hydride

Pang

Zhang

et al. 2018

J. Am. Chem. Soc.

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To determine the reaction pathways at a metal-ligand site in enzymes, we incorporated a terminal thiolate site into a diiron bridging hydride. Trithiolato diiron hydride, (μ-H)Fe(pdt)(dppbz)(CO)(SR) (1(μ-H)) [pdt = 1,3-(CH)S, dppbz = 1,2-CH(PPh), RS = 1,2-CyPCHS)], was synthesized directly by photoassisted oxidative addition of 1,2-CyPCHSH to Fe(pdt)(dppbz)(CO). The terminal thiolate in 1(μ-H) undergoes protonation, affording a thiol-hydride complex [1(μ-H)H]. Placing an acidic SH site adjacent to the Fe-H-Fe site allows intramolecular thiol-hydride coupling and releases H from [1(μ-H)H]. A diiron η-H intermediate in the formation of H is proposed, and is evidenced by the H/D exchange reactions of [1(μ-H)H] with D, DO, and CDOD. Isotopic exchange in [1(μ-D)H] is driven by an equilibrium isotope effect with 2.1 kJ/mol difference in free energy that favors [1(μ-H)D]. [1(μ-H)H] catalyzes H/D scrambling between H and DO or CDOD to produce HD. The reactions based on such a "proton-hydride" model provide insights into the reversible heterolytic cleavage of H by Hases.

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[Ni(NHPnPr3)(`S3')], the First Nickel Thiolate Complex Modeling the Nickel Cysteinate Site and Reactivity of [NiFe] Hydrogenase

Cited by 88 publications

References 3 publications

Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

H₂ Evolution from a Thiolate-Bound Ni(III) Hydride

Terminal Thiolate-Dominated H/D Exchanges and H₂ Release: Diiron Thiol–Hydride

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[Ni(NHPnPr3)(`S3')], the First Nickel Thiolate Complex Modeling the Nickel Cysteinate Site and Reactivity of [NiFe] Hydrogenase

Cited by 88 publications

References 3 publications

Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides

H2 Evolution from a Thiolate-Bound Ni(III) Hydride

Terminal Thiolate-Dominated H/D Exchanges and H2 Release: Diiron Thiol–Hydride

Contact Info

Product

Resources

About

H₂ Evolution from a Thiolate-Bound Ni(III) Hydride

Terminal Thiolate-Dominated H/D Exchanges and H₂ Release: Diiron Thiol–Hydride