Computational Study of Methane C–H Activation by Diiminopyridine Nitride/Nitridyl Complexes of 3d Transition Metals and Main-Group Elements

The C–H bond activation of methane using ^Ph,MePDI–M≡N [^Ph,MePDI = 2,6-(PhNCMe)₂C₅H₃N] (M = V, Mn, Fe, Co, Ni, Al, or P) has been studied via three reaction pathways: [2_σ + 2_π] addition, hydrogen atom abstraction (HAA), and direct insertion. The activating ligand is a nitride/nitridyl (N), with diiminopyridine (PDI) as the supporting ligand. Calculations show reasonable C–H activation barriers for Co, Ni, Al, and P ^Ph,MePDI nitrides, complexes that favor an HAA pathway. Electrophilic ^Ph,MePDI nitride complexes of the earlier metals with a nucleophilic actor ligandV, Mn, Fefollow a [2_σ + 2_π] addition pathway for methane activation. Free energy barriers for methyl migration, ^Ph,MePDI–M­(CH₃)NH → ^Ph,MePDI–M–N­(H)­CH₃, are also interesting in the context of alkane functionalization; discriminating factors in this mechanistic step include the strengths of the σ-bond and metal-actor ligand π-bond that are broken and the electrophilicity of the actor ligand to which methyl migrates

Computational Study of Methane C–H Activation by Diiminopyridine Nitride/Nitridyl Complexes of 3d Transition Metals and Main-Group Elements

The C–H bond activation of methane using ^Ph,MePDI–M≡N [^Ph,MePDI = 2,6-(PhNCMe)₂C₅H₃N] (M = V, Mn, Fe, Co, Ni, Al, or P) has been studied via three reaction pathways: [2_σ + 2_π] addition, hydrogen atom abstraction (HAA), and direct insertion. The activating ligand is a nitride/nitridyl (N), with diiminopyridine (PDI) as the supporting ligand. Calculations show reasonable C–H activation barriers for Co, Ni, Al, and P ^Ph,MePDI nitrides, complexes that favor an HAA pathway. Electrophilic ^Ph,MePDI nitride complexes of the earlier metals with a nucleophilic actor ligandV, Mn, Fefollow a [2_σ + 2_π] addition pathway for methane activation. Free energy barriers for methyl migration, ^Ph,MePDI–M­(CH₃)NH → ^Ph,MePDI–M–N­(H)­CH₃, are also interesting in the context of alkane functionalization; discriminating factors in this mechanistic step include the strengths of the σ-bond and metal-actor ligand π-bond that are broken and the electrophilicity of the actor ligand to which methyl migrates