Reductive Functionalization of a Rhodium(III)–Methyl Bond in Acidic Media: Key Step in the Electrophilic Functionalization of Methane

Journal Article · Thu Nov 06 04:00:00 EST 2014 · Organometallics

DOI:https://doi.org/10.1021/om5008456· OSTI ID:1385889

O’Reilly, Matthew E. ^[1]; Pahls, Dale R. ^[2]; Cundari, Thomas R. ^[2]; Gunnoe, T. Brent ^[1]

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1. Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, United States
2. Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, Texas 76203-5017, United States

The reductive functionalization of RhIII–Me bonds in acids is a key step for RhI/III-based catalysts for methane functionalization. Heating electronic-rich [tBu3terpy]Rh(Me)(Cl)I (1; tBu3terpy = 4,4',4''-tri-tert-butylterpyridine) in H2O, AcOD, or trifluoroacetic acid (HTFA) released a stoichiometric amount of methane. With use of a less donating ligand, [(NO2)3terpy]Rh(Me)(Cl)I (2; (NO2)3terpy = 4,4',4''-trinitroterpyridine), a mixture of CH4 and CH3X (X = Cl, TFA, OAc, OH) was obtained. The selectivity between MeX and CH4 was found to be dependent on the halide present (I– or Cl–). In a key experiment with the removal of one halide from 2, {[(NO2)3terpy]Rh(Me)Cl}{BF4} (3) was completely protonated in acidic solvent. DFT calculations were employed to investigate the mechanism of reductive functionalization and protonation.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Catalytic Hydrocarbon Functionalization (CCHF)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: SC0001298
• OSTI ID: 1385889
• Journal Information: Organometallics, Journal Name: Organometallics Journal Issue: 22 Vol. 33; ISSN 0276-7333
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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