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A Pd-PEPPSI-catalyzed (Pd = Palladium, PEPPSI = pyridine-enhanced precatalyst preparation stabilization and initiation) Suzuki-Miyaura cross-coupling of aryl esters via selective C–O cleavage at room temperature is reported. The developed catalyst system displays broad substrate scope with respect to both components under practical ambient reaction conditions using readily-available, cheap, modular, air- and moisturestable Pd-NHC precatalyst (NHC = N-heterocyclic carbene). The use of water proved crucial for achieving high reactivity in this coupling. The catalyst system represents the mildest conditions for the Suzuki-Miyaura cross-coupling of aryl esters reported to date. The protocol also allowed for achieving TON >1,000 (TON = turnover number) in the Suzuki-Miyaura ester coupling for the first time.
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A Bioinspired Molybdenum Catalyst for Aqueous Perchlorate Reduction
Perchlorate (ClO4–) is a pervasive, harmful, and inert anion on both Earth and Mars. Current technologies for ClO4– reduction entail either harsh conditions or multicomponent enzymatic processes. Herein, we report a heterogeneous (L)Mo–Pd/C catalyst directly prepared from Na2MoO4, a bidentate nitrogen ligand (L), and Pd/C to reduce aqueous ClO4– into Cl– with 1 atm of H2 at room temperature. A suite of instrument characterizations and probing reactions suggest that the MoVI precursor and L at the optimal 1:1 ratio are transformed in situ into oligomeric MoIV active sites at the carbon–water interface. For each Mo site, the initial turnover frequency (TOF0) for oxygen atom transfer from ClOx– substrates reached 165 h–1. The turnover number (TON) reached 3840 after a single batch reduction of 100 mM ClO4–. This study provides a water-compatible, efficient, and robust catalyst to degrade and utilize ClO4– for water purification and space exploration.
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- Award ID(s):
- 1932942
- PAR ID:
- 10231126
- Date Published:
- Journal Name:
- Journal of the American Chemical Society
- ISSN:
- 0002-7863
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/jacs.1c00595
