DFT Study on the Germanium Ion Activated C–H Bond in Methane

Thermal reactions of methane with the main group metal cations Ge＋,GeO＋,GeOH＋ and OGeOH＋ were investigated by state-of-the-art quantum chemical calculations.For GeO＋/CH_4,a H atom in CH_4 abstracted by the O atom in GeO＋ to form GeOH＋ and CH_3˙constitutes the channel mainly.The barrier-free process,combined with a large exothermicity,suggested a fast and efficient reaction in agreement with the experiment.For OGeOH＋ and CH_4,the intermediates and products of the most favorable path were below the reactant asymptote,and the reaction was easy to take place,while for Ge＋ and GeOH＋,the activation of C-H bond in methane was hard to happen under ambient temperature.The results showed,in contrast to the inertness of Ge~＋ and Ge OH＋,the GeO＋ and OGeOH＋ can activate the H_3C-H bond.The NBO natural charge and molecular electrostatic potential were used to analyze the four main group metal germanium constructions.The phenomenon suggested that ligands affect the electronic character and tune the chemical features of metal germanium center.