Electrophilic Impact of High-Oxidation State Main-Group Metal and Ligands on Alkane C - H Activation and Functionalization Reactions

High-oxidation state main-group metal complexes are potential alternatives to transition metals for electrophilic alkane C - H functionalization reactions. However, there is little known about how selection of the p-block, main-group metal and ligand impact alkane C - H activation and functionalization thermodynamics and reactivity. This work reports density functional theory calculations used to determine qualitative and quantitative features of C - H activation and metal-methyl functionalization energy landscapes for reaction between high-oxidation state d(10)s(0) In-III, Tl-III, Sn-IV, and Pb-IV carboxylate complexes with methane. While the main -group metal influences the C - H activation barrier height in a periodic manner, the carboxylate ligand has a much larger quantitative impact on C - H activation with stabilized carboxylate anions inducing the lowest barriers. For metal-methyl reductive functionalization reactions, the main -group metal dramatically influences the barrier heights, which are correlated to reaction thermodynamics and bond heterolysis energies as a model for two-electron reduction energies. Overall, this work begins to outline which main -group metals and carboxylate ligands could be useful for alkane functionalization systems that utilize electrophilic C - H activation and metal-alkyl functionalization reactions.