Methane activation by closed-shell tantalum sulfide anions TaS_(3)^(-)  

闭壳层硫化钽阴离子TaS_(3)^(-)活化甲烷

作　　者：Qian Li Xiao-Xiao Liu Qing-Yu Liu Sheng-Gui He 李千;刘晓晓;刘清宇;何圣贵(中国科学院化学研究所动态与稳态结构化学国家重点实验室,北京100190;中国科学院大学,北京100049;北京分子科学国家研究中心,中国科学院分子科学科教融合卓越创新中心,北京100190)

机构地区：[1]State Key Laboratory for Structural Chemistry of Unstable and Stable Species,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Beijing National Laboratory for Molecular Sciences and CAS Research/Education Centre of Excellence in Molecular Sciences,Beijing 100190,China

出　　处：《Chinese Journal of Chemical Physics》2024年第6期823-830,I0043,共9页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(No.92161205 and No.22121002);the Youth Innovation Promotion Association of CAS(No.2022033).

摘　　要：Methane is a vital feedstock while the intrinsic inertness of CH_(4)molecule hinders the conversion of methane under mild conditions.Investigating and understanding the mechanism of methane activation is of great importance in chemistry.In this study,tantalum sulfide anions TaS_(3)^(-)were generated by laser ablation method and mass-selected by a quadrupole mass filter to react with methane,ethane,and propane in an ion funnel trap reactor under thermal collision conditions.The reactant and product ions were detected by a time-of-flight mass spectrometer.Experimental results demonstrate that TaS_(3)^(-)is able to adsorb all of the alkane molecules and break the robust C-H bonds.Further density functional theory calculations reveal that TaS_(3)^(-)is a closed-shell species and effectively activates methane via the Ta^(δ+)-S^(δ-)Lewis acid-base pair(LABP,CH_(4)+Ta^(δ+)-S^(δ-)→CH_(3)-Ta-S-H).With a comparative study with NbS_(3)^(-)that contains the Nbδ+-S^(δ-)LABP,the higher reactivity of TaS_(3)^(-)than that of NbS_(3)^(-)can be attributed to the more acidity of Ta^(δ+)than that of Nbδ+.To the best of our knowledge,this study reports the first example of gas phase species TaS_(3)^(-)to activate methane through the metal-sulfur LABP under thermal collision conditions.甲烷是一种重要的化工原料,然而CH_(4)分子固有的惰性阻碍了其在温和条件下的转化.研究并理解甲烷活化的机制在化学领域具有重要的意义.本文通过激光溅射法制备了钽硫化物阴离子TaS_(3)^(-)并由四极质量过滤器选质,之后进入离子漏斗阱反应器中与甲烷、乙烷以及丙烷在热碰撞条件下反应,反应物与产物离子通过飞行时间质谱仪检测.实验结果表明,TaS_(3)^(-)能够吸附所有的烷烃分子并断裂坚固的C-H键.进一步的密度泛函理论计算显示TaS_(3)^(-)是一个闭壳层物种且能通过Ta^(δ+)-S^(δ-)路易斯酸碱对有效活化甲烷(CH_(4)+Ta^(δ+)-S^(δ-)→CH_(3)-Ta-S-H).通过与含有Nb^(δ+)-S^(δ-)路易斯酸碱对的NbS_(3)^(-)比较,TaS_(3)^(-)相较于NbS_(3)^(-)的高反应活性可以归因于Ta^(δ+)比Nb^(δ+)具有更强的酸性.本研究报道了第一例在热碰撞条件下通过金属-硫路易斯酸碱对活化甲烷的气相物种TaS_(3)^(-).

关 键 词：Methane activation Tantalum sulfide anions Lewis acid-base pair Gas phase clusters Reaction mechanisms 

分 类 号：O641.1[理学—物理化学]