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...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.展开更多
In this study, density functional theory calculations reveal how boron group ions M^+(M = B, Al, Ga, In, and Tl) directly convert carbon and methane into ethylene at room temperature. M^+ reacts with the carbon atom t...In this study, density functional theory calculations reveal how boron group ions M^+(M = B, Al, Ga, In, and Tl) directly convert carbon and methane into ethylene at room temperature. M^+ reacts with the carbon atom to form the cation MC^+. Then, the reaction of MC^+ with methane leads to the cleavage of metal-carbon bond and the formation of CH2CH2 through C-C coupling, with the ion M^+ serving as a leaving group. The cycle then begins again. The mechanism of C/CH4 system catalyzed by five ion types is investigated herein, and the reasons for the different reactivity of five ion types are determined. The moderate strength of the Al^+-C bond results in Al^+ being the only appropriate catalyst of M^+(M?=?B, Al, Ga, In, and Tl) that can catalyze methane and carbon into ethylene.展开更多
基金supported by the special steady growth science and technology foundation of Yanan Science and Technology Bureau(2017WZZ-08)the doctoral research program(YDBK2017-09)the research program(YD2016-09)of Yan’an University
文摘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.
基金Supported by the special steady growth science and technology foundation of Yanan Science and Technology Bureau(2017WZZ-08)the doctoral research program(YDBK2017-09)+1 种基金the research program(YD2016-09)(D2018009)of Yan’an University。
文摘In this study, density functional theory calculations reveal how boron group ions M^+(M = B, Al, Ga, In, and Tl) directly convert carbon and methane into ethylene at room temperature. M^+ reacts with the carbon atom to form the cation MC^+. Then, the reaction of MC^+ with methane leads to the cleavage of metal-carbon bond and the formation of CH2CH2 through C-C coupling, with the ion M^+ serving as a leaving group. The cycle then begins again. The mechanism of C/CH4 system catalyzed by five ion types is investigated herein, and the reasons for the different reactivity of five ion types are determined. The moderate strength of the Al^+-C bond results in Al^+ being the only appropriate catalyst of M^+(M?=?B, Al, Ga, In, and Tl) that can catalyze methane and carbon into ethylene.
