The conversion of methane CH4 to methanol CH3OH is a challenging process due to the high stability of the C-H bond in methane. However, using quantum chemical calculations, we can propose a plausible reaction mechanism for this conversion. One of the most common methods for this conversion is through the use of metal-oxo species as catalysts. Here, we will discuss a general mechanism involving a metal-oxo catalyst M=O .1. Activation of the metal-oxo catalyst: The metal-oxo species M=O gets activated by coordination with a suitable ligand L . This results in the formation of a more reactive metal-oxo complex L-M=O .L + M=O L-M=O2. Oxidative addition of methane: The activated metal-oxo complex L-M=O reacts with methane CH4 through an oxidative addition process. This step involves the cleavage of the C-H bond in methane and the formation of a new bond between the carbon atom and the metal center. The reaction results in the formation of a metal-methyl complex L-M-CH3 and a hydroxide ion OH- .L-M=O + CH4 L-M-CH3 + OH-3. Proton transfer: The hydroxide ion OH- formed in the previous step acts as a base and abstracts a proton from the metal-methyl complex L-M-CH3 . This results in the formation of a metal-hydroxide complex L-M-OH and a methyl radical CH3 .L-M-CH3 + OH- L-M-OH + CH34. Radical recombination: The methyl radical CH3 and the metal-hydroxide complex L-M-OH recombine to form the desired methanol product CH3OH and regenerate the metal-oxo catalyst M=O .L-M-OH + CH3 CH3OH + M=OOverall, the complete reaction mechanism for the conversion of methane to methanol using quantum chemical calculations can be summarized as follows:L + M=O + CH4 L-M=O + CH3OHIt is important to note that the specific details of the reaction mechanism, such as the nature of the metal-oxo catalyst and the ligand, may vary depending on the specific system being studied. Quantum chemical calculations can help to determine the most favorable reaction pathway and the energetics of each step in the mechanism.