A (U)MP2(full) and (U)CCSD(T) theoretical investigation on the substituent effect on the cation-pi interactions between Na+ and LCCL (L = -H, -CH3, -OH, -F, -Cl, CO, NN, CN-, NC- and OH-)

作者：Yang, Ji-hua; Ren, Fu-de^*

来源：Journal of Molecular Structure (Theochem), 2010, 956(1-3): 1-9.

DOI：10.1016/j.theochem.2010.06.014

• CC multiple-bond
• Substituent effect
• Cation-pi interaction
• Electron density shifts

The substituent effect on the cation-pi interactions are investigated between Na+ and LCCL (L = -H, -CH3, -OH, -F, -Cl, CO, NN, CN-, NC- and OH-) using (U)MP2(full) and (U)CCSD(T) methods at 6-311+G(2d) (or 6-311++G(2d,p)) and aug-cc-pVTZ levels. A C C triple-bond contraction is observed in (HOC COH)(2-)center dot center dot center dot Na+. The electron-donating substituent increases electron density of the CC multiple-bond by means of the p-pi, pi-pi conjugative or sigma-pi hyperconjugative effects, resulting in the increased cation-pi interaction compared with that of the unsubstituted HCCH center dot center dot center dot Na+, while the electron-withdrawing substituent decreases the cation-pi interaction. Furthermore, the stronger the electron-donating ability of the substituent is the higher binding energy the complex holds. Moreover, the more lost density from the electron-donating -CH3, OH, NN or OH- substituent in complex than in monomer is shifted to the pi-orbital of the CC bond upon complexation. The analyses of the "truncated" model, natural bond orbital (NBO). atoms in molecules (AIM) and electron density shifts reveal the nature of the substituent effects and explain the origin of the C C bond contraction in (HOC COH)(2-) center dot center dot center dot Na+.

• 出版日期2010-9-30
• 单位中北大学