Methane hydroxylation at the dinuclear copper site of particulate methane monooxygenase (pMMO) is studied by using density functional theory (DFT) calculations. The electronic and structural properties of the dinuclear copper species of bis(μ-oxo)CuIICuIII and Cu IIICuIII are discussed with respect to the C-H bond activation of methane. The bis(μ-oxo)CuIICuIII species is highly reactive and considered to be an active species for the conversion of methane to methanol by pMMO, whereas the bis(μ-oxu)CuIIICu III species is unable to react with methane as it is. If a Cu-O bond of the bis(μ-oxo)CuIIICuIII species is cleaved, the resultant CuIIICuIII species, in which only one oxo ligand bridges the two copper ions, can activate methane. However, its energetics for methane hydroxylation is less favorable than that by the bis(μ-oxo)Cu IICuIII species. The DFT calculations show that the bis(μ-oxo)CuIICuIII species is more effective for the activation of methane than the bis(μ-oxu)CuIIICuII species. The reactive bis(μ-oxo)CuIICuIII species can be created either from the electron injection to the bis(μ-oxo)Cu IIICuIII species or from the O-O bond cleavage in the μ-η1-η2-peroxoCuICuII species.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry