摘要:
The reductive functionalization of (RhMe)-Me-III bonds in acids is a key step for Rh-I/III-based catalysts for methane functionalization. Heating electronic-rich [(t)Bu(3)terpy]-Rh(Me)(Cl)I (1; (t)Bu(3)terpy = 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)(3)terpy]Rh(Me)(Cl)I (2; (NO2)(3)terpy = 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)(3)terpy]Rh(Me)Cl}{BF4} (3) was completely protonated in acidic solvent. DFT calculations were employed to investigate the mechanism of reductive functionalization and protonation.