Acta Chimica Sinica ›› 1999, Vol. 57 ›› Issue (8): 852-859.

Original Articles

### 阳离子－π体系相互作用的理论研究 2: 铵离子－二苯复合物体系的密度泛函研究

1. 中国科学院上海药物研究所;中国科学院新药研究国家重点实验室;苏州大学化学系
• 出版日期:1999-08-15 发布日期:1999-08-15

### Theoretical studies on cation -π interactions 2: Density -funtional theory investigation on the configurations of and interactions in ammonium cation -bibenzene complexes

ZHU WEILIANG;JIANG HUALIANG;TAN XIAOJIAN;CHEN JIANZHONG;DI YUFENG;GU JIANDE;LIN MAOWEI;CHEN KAIXIAN;JI RUYUN;CAO YANG

• Online:1999-08-15 Published:1999-08-15

Density - functional theory (DFT) B3lLYP/6 - 31G^* approach has been employed to calculate the possible configurations ammonium - bibenzene (C~6H~6…NH~4^+…C~6H~6) complex. The calculation results indicate that the most stable structure of the complex is the configuration where the ammonium cation located between two benzenes with two hydrogen atoms pointing to each benzene ring.The calculated IR spectrum shows that the geometry is reasonable.The bond length, total atomic charges,the coefficiet of the molecularorbital, frontier orbital energys, and Mullicken bonding population of the complex indicate that the binding between the ammonium and two benzenes involved the s-π interaction between hydrogens of ammonium and the carbon atoms of benzenes near to the hydrogens of ammonium, with electron transfer occured from the two benzne rings to ammonium,forminmg a charge transfer complex.The calculated results also imply that,similar to that of the ammonium caton-benzene transfer complex, the interaction characteristic of the ammonium cation-bibenzene complex is a typical hydrogen bond.The calculated thermodynamic parameters demonstrate this feature.The nomal mode analysis of the predicted vibrational frequency shows that the characteristic vibration mode of the complex is located at about 230cm^-^1, correspondeding to the back and forth vibration of the ammonium cation paralleled to the bezene rings.

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