H₂ Evolution from a Thiolate-Bound Ni(III) Hydride
- Creators
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Gu, Nina X.
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Oyala, Paul H.
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Peters, Jonas C.
Abstract
Terminal Ni^(III) hydrides are proposed intermediates in proton reduction catalyzed by both molecular electrocatalysts and metalloenzymes, but well-defined examples of paramagnetic nickel hydride complexes are largely limited to bridging hydrides. Herein, we report the synthesis of an S = 1/2, 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 also recently been reported to undergo bimolecular H–H coupling.
Additional Information
© 2020 American Chemical Society. Received: January 19, 2020; Published: April 4, 2020. The authors acknowledge Gerri Roberts for preliminary data and Dr. Michael Takase and Lawrence Henling for assistance with X-ray crystallography. This work was supported by the Department of Energy (DOE-0235032) and NSF-GRFP (N.X.G.). The Caltech EPR facility was supported by the NSF (NSF-1531940) and the Dow Next Generation Educator Fund. The X-ray Crystallography Facility in the Beckman Institute at Caltech was supported by the Dow Next Generation Instrumentation Grant. The authors declare no competing financial interest.Attached Files
Supplemental Material - ja0c00712_si_001.pdf
Supplemental Material - ja0c00712_si_002.cif
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Additional details
- Eprint ID
- 102349
- DOI
- 10.1021/jacs.0c00712
- Resolver ID
- CaltechAUTHORS:20200406-103934930
- Department of Energy (DOE)
- DOE-0235032
- NSF Graduate Research Fellowship
- NSF
- 153194
- Dow Next Generation Educator Fund
- Created
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2020-04-06Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field