Metal–organic frameworks (MOFs) have been extensively used for single‐site catalysis and light harvesting, but their application in multicomponent photocatalysis is unexplored. We report here the successful incorporation of an IrIIIphotoredox catalyst and a NiIIcross‐coupling catalyst into a stable Zr12MOF, Zr12‐Ir‐Ni, to efficiently catalyze C−S bond formation between various aryl iodides and thiols. The proximity of the IrIIIand NiIIcatalytic components to each other (ca. 0.6 nm) in Zr12‐Ir‐Ni greatly facilitates electron and thiol radical transfers from Ir to Ni centers to reach a turnover number of 38 500, an order of magnitude higher than that of its homogeneous counterpart. This work highlights the opportunity in merging photoredox and organometallic catalysts in MOFs to effect challenging organic transformations.
Metal–organic frameworks (MOFs) have been extensively used for single‐site catalysis and light harvesting, but their application in multicomponent photocatalysis is unexplored. We report here the successful incorporation of an IrIIIphotoredox catalyst and a NiIIcross‐coupling catalyst into a stable Zr12MOF, Zr12‐Ir‐Ni, to efficiently catalyze C−S bond formation between various aryl iodides and thiols. The proximity of the IrIIIand NiIIcatalytic components to each other (ca. 0.6 nm) in Zr12‐Ir‐Ni greatly facilitates electron and thiol radical transfers from Ir to Ni centers to reach a turnover number of 38 500, an order of magnitude higher than that of its homogeneous counterpart. This work highlights the opportunity in merging photoredox and organometallic catalysts in MOFs to effect challenging organic transformations.
more » « less- NSF-PAR ID:
- 10076936
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 57
- Issue:
- 43
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 14090-14094
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Although many monometallic active sites have been installed in metal–organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF‐NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF‐253 with the formula of Al(OH)(2,2′‐bipyridine‐5,5′‐dicarboxylate) for
Z ‐selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β‐unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅−)NiII(μ 2‐H)2NiII(bpy⋅−) as the active catalyst. MOF‐NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution‐inaccessible Earth‐abundant bimetallic MOF catalysts for sustainable catalysis. -
more » « less
Abstract Although many monometallic active sites have been installed in metal–organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF‐NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF‐253 with the formula of Al(OH)(2,2′‐bipyridine‐5,5′‐dicarboxylate) for
Z ‐selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β‐unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅−)NiII(μ 2‐H)2NiII(bpy⋅−) as the active catalyst. MOF‐NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution‐inaccessible Earth‐abundant bimetallic MOF catalysts for sustainable catalysis. -
more » « less
Abstract This work demonstrates the dominance of a Ni(0/II/III) cycle for Ni‐photoredox amide arylation, which contrasts with other Ni‐photoredox C‐heteroatom couplings that operate via Ni(I/III) self‐sustained cycles. The kinetic data gathered when using different Ni precatalysts supports an initial Ni(0)‐mediated oxidative addition into the aryl bromide. Using NiCl2as the precatalyst resulted in an observable induction period, which was found to arise from a photochemical activation event to generate Ni(0) and to be prolonged by unproductive comproportionation between the Ni(II) precatalyst and the in situ generated Ni(0) active species. Ligand exchange after oxidative addition yields a Ni(II) aryl amido complex, which was identified as the catalyst resting state for the reaction. Stoichiometric experiments showed that oxidation of this Ni(II) aryl amido intermediate was required to yield functionalized amide products. The kinetic data presented supports a rate‐limiting photochemically‐mediated Ni(II/III) oxidation to enable C−N reductive elimination. An alternative Ni(I/III) self‐sustained manifold was discarded based on EPR and kinetic measurements. The mechanistic insights uncovered herein will inform the community on how subtle changes in Ni‐photoredox reaction conditions may impact the reaction pathway, and have enabled us to include aryl chlorides as coupling partners and to reduce the Ni loading by 20‐fold without any reactivity loss.
-
more » « less
Abstract This work demonstrates the dominance of a Ni(0/II/III) cycle for Ni‐photoredox amide arylation, which contrasts with other Ni‐photoredox C‐heteroatom couplings that operate via Ni(I/III) self‐sustained cycles. The kinetic data gathered when using different Ni precatalysts supports an initial Ni(0)‐mediated oxidative addition into the aryl bromide. Using NiCl2as the precatalyst resulted in an observable induction period, which was found to arise from a photochemical activation event to generate Ni(0) and to be prolonged by unproductive comproportionation between the Ni(II) precatalyst and the in situ generated Ni(0) active species. Ligand exchange after oxidative addition yields a Ni(II) aryl amido complex, which was identified as the catalyst resting state for the reaction. Stoichiometric experiments showed that oxidation of this Ni(II) aryl amido intermediate was required to yield functionalized amide products. The kinetic data presented supports a rate‐limiting photochemically‐mediated Ni(II/III) oxidation to enable C−N reductive elimination. An alternative Ni(I/III) self‐sustained manifold was discarded based on EPR and kinetic measurements. The mechanistic insights uncovered herein will inform the community on how subtle changes in Ni‐photoredox reaction conditions may impact the reaction pathway, and have enabled us to include aryl chlorides as coupling partners and to reduce the Ni loading by 20‐fold without any reactivity loss.
