【作者】 张莹；

【导师】 丁益宏；

【作者基本信息】 吉林大学 ， 物理化学， 2022， 硕士

【摘要】 非共价相互作用包括氢键、卤键、磷键、π···π堆积作用、CH···π作用以及tetrel bond等,其在化学、生物学等许多重要领域都占据主导地位。其中,CH···π作用是指CH键和π电子体系之间的非共价相互作用。Tetrel bond则是第IV主族原子与路易斯碱之间形成的一种非共价相互作用。截至目前,人们将研究焦点主要集中在了包含CH···π作用和tetrel bond作用的复合物的相互作用能大小上,然而却忽视了复合物的异构化稳定性。而它们的异构化稳定性将决定着这两类非共价相互作用所形成复合物的存在寿命,对它们的光谱检测以及在分子识别和组装中起到了很重要的作用。因此,对这两类复合物异构化稳定性进行深入研究具有很重要的意义。基于此,在本文中,我们首次对C₂（ML_n）₂（M=Li,Na,K,Cu,Ag,Au;L=PH₃;n=0,1）与CHCl₃形成的CH···π复合物以及C₂（ML_n）₂与GeH₃F形成的π···σ-hole tetrel bond复合物的异构化稳定性进行了详细的探讨,主要内容如下:（1）本文对C₂（ML_n）₂与CHCl₃形成的CH···π复合物的异构化稳定性进行了深入研究,结果表明:当M为碱金属Li、Na和K时,无论在M上是否引入PH₃配体,即M=Li、Na和K;L=PH₃;n=0,1时,其对应的具有CH···π作用的复合物异构化稳定性都比较差（能垒为0.06～2.74 kcal/mol）。其中作用位点发生改变,由CHCl₃垂直进攻转变成直线进攻C₂,异构成具有CH···lone pair（lp）（lp来自炔基中的C）作用的复合物。当M替换为钱币金属Cu、Ag和Au时,且不引入PH₃配体时,即M=Cu、Ag和Au;L=PH₃;n=0时,虽然碳碳三键不发生扭转,但CHCl₃发生旋转,异构化成Cl→M配位形式的复合物。若在M上引入PH₃配体,即M=Cu、Ag和Au;L=PH₃;n=1时,该复合物的异构化稳定性得到显著提高（能垒为21.14～37.96 kcal/mol）,不容易发生异构化,维持住了CH···π作用。此外,采用对称性匹配微扰理论（Symmetry-Adapted Perturbation Theory,SAPT）的研究方法,对C₂（MPH₃）₂···CHCl₃（M=Cu,Ag,Au）的CH···π复合物的相互作用能的组成进行分析,结果表明,其中静电作用的贡献较为显著。并且,该复合物的相互作用能（-8.58～-10.56 kcal/mol）超过了“典型的”CH···π作用的复合物相互作用能（<3 kcal/mol）,甚至达到了水分子的二聚体（H₂O···H₂O）中的氢键（约5 kcal/mol）的2倍左右。（2）本文对C₂（ML_n）₂与GeH₃F形成的π···σ-hole tetrel bond复合物（碳碳三键中π电子与Ge H₃F中Ge作用）的异构化稳定性进行系统研究。结果发现:无论是否向碱金属M（M=Li,Na,K）上引入PH₃配体,该复合物的异构化稳定性均比较差（能垒小于1 kcal/mol）,其中作用位点发生改变,由Ge H₃F垂直进攻转变成直线进攻C₂,生成具有lone pair（lp）···σ-hole tetrel bond（C₂中C的lp与Ge H₃F中Ge作用）的复合物。若M替换为钱币金属Cu、Ag和Au时,且在M上不引入PH₃时,Ge H₃F发生旋转,异构化成Ge与金属M作用的复合物。然而,当向钱币金属M（M=Cu,Ag,Au）上引入PH₃时,该复合物异构化稳定性良好（能垒为20.81～32.92 kcal/mol）,不易异构化,维持住了π···σ-hole tetrel bond,为C₂（ML_n）₂与Ge H₃F形成的π···σ-hole tetrel bond复合物的实验表征提供了有效的理论依据。更多还原

【Abstract】 Non-covalent interactions include hydrogen bond,halogen bond,pnicogen bond,π···πstacking interactions,CH···πinteractions,and tetrel bond,which are dominant in many important fields such as chemistry and biology.The CH···πinteractions are a kind of non-covalent interaction between the CH bond and theπsystem.Tetrel bond is a kind of non-covalent interaction between Group IV atom and Lewis base.So far,researchers have focused on the interaction energies of complexes involving CH···πinteractions and tetrel bond interactions,but have neglected the isomerization stability of the formed complexes.However,their isomerization stability determines the lifetime of the complexes formed by these two types of non-covalent interactions,and plays an important role in their spectral detection,molecular recognition and assembly.Therefore,the in-depth study of the isomerization stability of these two types of complexes is of great significance.Based on this,in this paper,we have discussed the isomerization stability of the CH···πcomplexes formed by C₂（ML_n）₂（M=Li,Na,K,Cu,Ag,Au;L=PH₃;n=0,1）and CHCl₃ and theπ···σ-hole tetrel bond complexes formed by C₂（ML_n）₂and GeH₃F in detail.The main contents are as follows:（1）In this paper,the isomerization stability of CH···π complexes formed by C₂（ML_n）₂and CHCl₃ was deeply studied.The results showed that:when M is an alkali metal Li,Na,K,whether PH₃ ligands are introduced to M,i.e.,M=Li,Na and K;L=PH₃;n=0,1,the isomerization stability（with the barrier of 0.06～2.74 kcal/mol）of the corresponding complexes with CH···πinteractions is relatively poor.Among them,the action site is changed,from CHCl₃ vertical attack C₂ to linear attack C₂,forming a complex with CH···lone pair（lp）（lp coming from the C in the alkynyl）interactions.When M is replaced by the coinage metals Cu,Ag and Au,without introducing the PH₃ligands,that is,M=Cu,Ag and Au;L=PH₃;n=0,although the carbon-carbon triple bond is not distorted,the complex is easily converted to the isomer in the Cl→M coordination form.If PH₃ ligands are introduced to M,i.e.,M=Cu,Ag and Au;L=PH₃;n=1,the isomerization stability of the complex is significantly increased（with the barrier of 21.14～37.96 kcal/mol）,isomerization is not easy to occur,and the CH···πinteractions are maintained.In addition,the composition of the interaction energy of the CH···π complexes of C₂（MPH₃）₂···CHCl₃（M=Cu,Ag,Au）was analyzed by using the Symmetry-Adapted Perturbation Theory（SAPT）.It showed that the electrostatic interaction is the major source of the attraction.Moreover,the interaction energies（-8.58～-10.56 kcal/mol）of the complexes exceed the"typical"CH···πinteraction complexes（<3 kcal/mol）and even reach twice as high as the hydrogen bonding energy in the water dimer（H₂O···H₂O）（about 5 kcal/mol）.（2）In this paper,the isomerization stability of theπ···σ-hole tetrel bond complexes formed by C₂（ML_n）₂ and Ge H₃F（the interaction between theπelectron in the carbon-carbon triple bond and the Ge in Ge H₃F）was systematically studied.The result demonstrated that:regardless of whether the PH₃ ligand is introduced into the alkali metal M（M=Li,Na,K）,the isomerization stability of the complex is relatively poor（with the barrier less than 1 kcal/mol）,in which the action site is changed,from Ge H₃F vertical attack C₂ to linear attack C₂,forming a complex with lone pair（lp）···σ-hole tetrel bond（The lp of C in C₂ interacting with Ge in Ge H₃F）interactions.When M is replaced by coinage metals Cu,Ag and Au,and PH₃ is not introduced on M,Ge H₃F rotates and isomerizes into a complex that interacts with metal M.However,when PH₃is introduced to the coinage metals M（M=Cu,Ag,Au）,the isomerization stability of the complex is good（with the barrier of 20.81～32.92 kcal/mol）.These structures are not easy to isomerize and maintains theπ···σ-hole tetrel bond.It provides an effective theoretical basis for the experimental characterization of theπ···σ-hole tetrel bond complexes formed by C₂（ML_n）₂ and GeH₃F.更多还原