Be_(2)H_(3)L_(2)^(-)(L=CH_(3)和F-I):含有超短铍-铍间距的飙卤素离子  

Be_(2)H_(3)L_(2)^(-)(L=CH_(3) and F-I):Hyperhalogen Anions with Ultrashort Beryllium-Beryllium Distances

作　　者：赵雪锋 晋博 袁彩霞[2] 周成勇[1] 吴艳波 Xuefeng Zhao;Bo Jin;Chengyong Zhou;Caixia Yuan;Yanbo Wu(Department of Chemistry,Changzhi University,Changzhi 046011,China;Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province,Institute of Molecu lar Science,Shanxi University,Taiyuan 030006,China)

机构地区：[1]长治学院化学系,长治046011 [2]山西大学分子科学研究所能源转换与存储材料山西省重点实验室,太原030006

出　　处：《Chinese Journal of Chemical Physics》2023年第2期224-230,I0029-I0041,I0055,共21页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(No.22073058);the Natural Science Foundation of Shanxi Province(No.201901D111018 and No.20210302124682);the Scientific and Technologial Innovation Programs of Higher Education Institutions in Shanxi(No.2020L0618).

摘　　要：超碱金属离子和超卤素离子通常由不同的核心结构来构建.结合之前报道的Be_(2)H_(3)L2+(L'=NHg和Ne--Xe)是超碱金属离子,本文通过设计超卤素离子Be_(2)H_(3)L2(L=CH_(3)和F-I)证明超碱金属离子和超卤素离子均可使用Be_(2)H_(3)作为核心部分来构建.超卤素离子Be_(2) H_(3)L_(2)^(-)(L=CH_(3)和F-I)是以Be_(2)H_(3)L′_(2)^(+)(L'=NH_(3)和Ne-Xe)为模板,通过L-等电子体取代L'得到.该取代反应放出大量的热,说明Be_(2)H_(3)L_(2)^(-)比Be_(2)H_(3)L2+更稳定.同时,Be_(2)H_(3)L_(2)^(-)(L=CHg和F-I)也具有稳定的电子结构,其HOMO-LUMO能隙值范围为4.69~5.38eV.值得注意的是,这些阴离子结构的垂直电离能均大于5.00 eV(5.38~6.06 eV),可称为飙卤素离子,并且这些结构中的Be-Be距离为1.776~1.826 A,属于超短金属-金属间距.在设计的五个结构中,其中Be_(2)H_(3)L_(2)^(-)(L=CH_(3)、CI和Br)是动力学稳定的全局极小结构,希望这些结构能在负离子光电子能谱中得到并进行表征.本文同时还设计了具有保护基团的分子[t-Bu-Be_(2)H_(3)-t-Bu]-(t-Bu=叔丁基),可作为凝聚相下合成和分离的目标分子.The superalkali cations and superhalogen anions commonly have different type of core moieties.Based on the previous reports that Be_(2)H_(3)L′_(2)^(+)(L′=NH_(3) and noble gases Ne−Xe)are superalkali cations,in the present work,we designed the superhalogen anions Be_(2)H_(3)L_(2)^(-)(L=CH_(3) and halogens F−I),and both superalkali cations and superhalogen anions can be constructed using Be_(2)H_(3) as the core moiety.The newly designed Be_(2)H_(3)L_(2)^(-)species are much more stable than their isoelectronic cationic counterparts Be_(2)H_(3)L′_(2)^(+),as can be reflected by the highly exergonic substitution reaction of L′ligand in Be_(2)H_(3)L′_(2)^(+)with isoelectronic L−to give Be_(2)H_(3)L_(2)^(-).These anionic species possess the well-defined electronic structure,which can be proven by their large HOMO−LUMO gaps of 4.69 eV to 5.38 eV.It is remarkable that Be_(2)H_(3)L_(2)^(-)can be regarded as the hyperhalogen anions due to the extremely high vertical detachment energies(5.38 eV to 6.06 eV)and the Be−Be distances in these species(1.776Åto 1.826Å)are short in ultrashort metal-metal distances(defined as dM−M<1.900Å)between main group metals.In the designed five small model species,three of them,i.e.Be_(2)H_(3)L_(2)^(-)(L=CH_(3),Cl,and Br),are kinetical viable global energy minima,which are the promising target for generation and characterization in anion photoelectron spectroscopy.The analogue molecule[t-Bu−Be_(2)H_(3)−t-Bu]−with bulky protecting tert-butyl(t-Bu)groups is designed as a possible target for synthesis and isolation in condensed states.

关 键 词：飙卤素离子 超短Be-Be间距 电子结构 稳定性 密度泛函 

分 类 号：O643.12[理学—物理化学]