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Published June 7, 2016 | Version Supplemental Material + Published
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Proton–hydride tautomerism in hydrogen evolution catalysis

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of Kansas

Abstract

Efficient generation of hydrogen from renewable resources requires development of catalysts that avoid deep wells and high barriers. Information about the energy landscape for H_2 production can be obtained by chemical characterization of catalytic intermediates, but few have been observed to date. We have isolated and characterized a key intermediate in 2e^– + 2H^+ → H_2 catalysis. This intermediate, obtained by treatment of Cp*Rh(bpy) (Cp*, η^5-pentamethylcyclopentadienyl; bpy, κ^2-2,2′-bipyridyl) with acid, is not a hydride species but rather, bears [η^4-Cp*H] as a ligand. Delivery of a second proton to this species leads to evolution of H_2 and reformation of η^5-Cp* bound to rhodium(III). With suitable choices of acids and bases, the Cp*Rh(bpy) complex catalyzes facile and reversible interconversion of H^+ and H_2.

Additional Information

© 2016 National Academy of Sciences. Contributed by Harry B. Gray, April 17, 2016 (sent for review February 4, 2016; reviewed by Alexander Miller and David Milstein). Published online before print May 24, 2016. S.I.J. thanks Dr. Robert Nielsen for helpful discussions. This research, which was carried out in part at the Molecular Materials Research Center and the Laser Resource Center of the Beckman Institute (California Institute of Technology), was supported by NSF CCI Solar Fuels Program CHE-1305124. S.I.J. and J.D.B. acknowledge fellowships from the Resnick Sustainability Institute at Caltech. Author contributions: S.I.J., D.G.V., J.R.W., H.B.G., and J.D.B. designed research; L.M.A.Q., S.I.J., S.L.C., W.V., M.K.T., and J.D.B. performed research; W.A.G. contributed new reagents/analytic tools; L.M.A.Q., S.I.J., S.L.C., W.V., M.K.T., D.G.V., J.R.W., H.B.G., and J.D.B. analyzed data; and S.I.J., J.R.W., H.B.G., and J.D.B. wrote the paper. Reviewers: A.M., University of North Carolina; and D.M., The Weizmann Institute of Science. The authors declare no conflict of interest. Data deposition: The atomic coordinates and structure factors have been deposited in the Cambridge Crystallographic Data Centre (accession no. 1424707). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1606018113/-/DCSupplemental.

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Supplemental Material - pnas.1606018113.sapp.pdf

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Additional details

Identifiers

PMCID
PMC4988566
Eprint ID
67333
DOI
10.1073/pnas.1606018113
Resolver ID
CaltechAUTHORS:20160525-080847791

Related works

Describes
10.1073/pnas.1606018113 (DOI)

Funding

NSF
CHE-1305124
Resnick Sustainability Institute

Dates

Created
2016-05-25
Created from EPrint's datestamp field
Updated
2022-04-27
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Resnick Sustainability Institute, CCI Solar Fuels