Boryl−Metal Bonds Facilitate Cobalt/Nickel-Catalyzed Olefin Hydrogenation
- Creators
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Lin, Tzu-Pin
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Peters, Jonas C.
Abstract
New approaches toward the generation of late first-row metal catalysts that efficiently facilitate two-electron reductive transformations (e.g., hydrogenation) more typical of noble-metal catalysts is an important goal. Herein we describe the synthesis of a structurally unusual S = 1 bimetallic Co complex, [(^(Cy)PBP)CoH]_2 (1), supported by bis(phosphino)boryl and bis(phosphino)hydridoborane ligands. This complex reacts reversibly with a second equivalent of H_2 (1 atm) and serves as an olefin hydrogenation catalyst under mild conditions (room temperature, 1 atm H_2). A bimetallic Co species is invoked in the rate-determining step of the catalysis according to kinetic studies. A structurally related Ni^INi^I dimer, [(^(Ph)PBP)Ni]_2 (3), has also been prepared. Like Co catalyst 1, Ni complex 3 displays reversible reactivity toward H_2, affording the bimetallic complex [(^(Ph)PBHP)NiH]_2 (4). This reversible behavior is unprecedented for Ni^I species and is attributed to the presence of a boryl–Ni bond. Lastly, a series of monomeric (^(tBu)PBP)NiX complexes (X = Cl (5), OTf (6), H (7), OC(H)O (8)) have been prepared. The complex (^(tBu)PBP)NiH (7) shows enhanced catalytic olefin hydrogenation activity when directly compared with its isoelectronic/isostructural analogues where the boryl unit is substituted by a phenyl or amine donor, a phenomenon that we posit is related to the strong trans influence exerted by the boryl ligand.
Additional Information
© 2014 American Chemical Society. Received: May 9, 2014. Publication Date (Web): September 2, 2014. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub supported through the Office of Science of the U.S. Department of Energy under Award DE-SC0004993. We thank Dr. David C. Leitch, Dr. Yichen Tan, and Dr. Charles C. McCrory for insightful discussions on kinetics. We also thank Prof. Gerard Parkin for insightful discussions on bonding.Attached Files
Supplemental Material - ja504667f_si_001.pdf
Supplemental Material - ja504667f_si_002.cif
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Additional details
- Eprint ID
- 50069
- DOI
- 10.1021/ja504667f
- Resolver ID
- CaltechAUTHORS:20140926-131812982
- Department of Energy (DOE)
- DE-SC0004993
- Created
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2014-09-26Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field