摘要
最近AnstÖter,et al.发表了对阴离子-π复合物(I-.C6F6)的第一个定量谱学测量[J.Am.Chem.Soc.141,6132 (2019)],认为成键作用中相关作用占41%,静电作用占占23%,得出相关作用占主导的结论.本研究表明,该文献的"静电作用"中混入了Pauli排斥作用,后者在数值上抵消了前者的作用.在复合物I-.C6F6中,发现静电作用是相关作用的两倍多,因而阴离子-π复合物中仍应是静电作用占主导.
Recently,AnstÖter and co-workers[J.Am.Chem.Soc.141,6132(2019)]have provided the first photoelectron spectroscopic determination of the anion-πbond strength(De)using iodide-hexafluorobenzene(I-·C6F6)as the archetypical system.In combination with an equation-of-motion coupled cluster theory,namely EOM-IP-CCSD(d T),using Dunning’s aug-cc-p VDZ(a VDZ)basis set,Dein I-·C6F6 was found to be-0.53 e V with an uncertainty less than±0.03 e V.The interaction was claimed to arise for a large part from correlation forces(41%)with only a 23%contribution from electrostatic forces.In the present work,we performed the coupled-cluster with single and double and perturbative triple excitations,CCSD(T),calculations.We found that CCSD(T)/a VDZ can have an uncertainty up to 0.113 e V due to the basis set incompleteness.Our calculations disclosed that the previous calculations on the electrostatic contribution are concealed by the contributions from the exchange and Pauli repulsion.The electrostatic contribution is actually determinant,being more than double of the correlation contribution in the I-·C6F6 complex at the equilibrium binding distance.
作者
刘章云
陈征
徐昕
Zhang-yun Liu;Zheng Chen;Xin Xu(Collaborative Innovation Center of Chemistry for Energy Materials,Shanghai Key Laboratory of Molec-ular Catalysis and Innovative Materials,MOE Key Laboratory of Computational Physical Sciences,Department of Chemistry,Fudan University,Shanghai 200433,China)
基金
supported by the National Natural Science Foundation of China(No.21688102 and No.91027044)。
