Silica Supported Organometallic Ir I Complexes Enable Efficient Catalytic Methane Borylation.

Autor: Staples O; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States., Ferrandon MS; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Laurent GP; US DOE, Ames National Laboratory, Ames, Iowa 50011, United States.; Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), F-75005 Paris, France., Kanbur U; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Kropf AJ; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Gau MR; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States., Carroll PJ; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States., McCullough K; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Sorsche D; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States., Perras FA; US DOE, Ames National Laboratory, Ames, Iowa 50011, United States.; Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States., Delferro M; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Kaphan DM; Chemical Sciences and Engineering, Argonne National Laboratory Division, Lemont, Illinois 60439, United States., Mindiola DJ; Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Jazyk: angličtina
Zdroj: Journal of the American Chemical Society [J Am Chem Soc] 2023 Apr 12; Vol. 145 (14), pp. 7992-8000. Date of Electronic Publication: 2023 Mar 30.
DOI: 10.1021/jacs.2c13612
Abstrakt: Catalytic C-H borylation is an attractive method for the conversion of the most abundant hydrocarbon, methane (CH 4 ), to a mild nucleophilic building block. However, existing CH 4 borylation catalysts often suffer from low turnover numbers and conversions, which is hypothesized to result from inactive metal hydride agglomerates. Herein we report that the heterogenization of a bisphosphine molecular precatalyst, [(dmpe)Ir(cod)CH 3 ], onto amorphous silica dramatically enhances its performance, yielding a catalyst that is 12-times more efficient than the current standard for CH 4 borylation. The catalyst affords over 2000 turnovers at 150 °C in 16 h with a selectivity of 91.5% for mono- vs diborylation. Higher catalyst loadings improve yield and selectivity for the monoborylated product (H 3 CBpin) with 82.8% yield and >99% selectivity being achieved with 1255 turnovers. X-ray absorption and dynamic nuclear polarization-enhanced solid-state NMR spectroscopic studies identify the supported precatalyst as an Ir I species, and indicate that upon completion of catalysis, multinuclear Ir polyhydrides are not formed. This is consistent with the hypothesis that immobilization of the organometallic Ir species on a surface prevents bimolecular decomposition pathways. Immobilization of the homogeneous Ir I fragment onto amorphous silica represents a unique and simple strategy to improve the TON and longevity of a CH 4 borylation catalyst.
Databáze: MEDLINE
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