物理化学学报 >> 2008, Vol. 24 >> Issue (09): 1631-1636.doi: 10.3866/PKU.WHXB20080918

研究论文 上一篇    下一篇

环双(对-蒽基-对草快)的分子识别与谱学性质

王维 邵世群 周慧 滕启文   

  1. 浙江大学化学系, 杭州 310027; 浙江树人大学生物与环境工程学院, 杭州 310015
  • 收稿日期:2008-04-30 修回日期:2008-06-10 发布日期:2008-09-10
  • 通讯作者: 滕启文 E-mail:wushi@zju.edu.cn

Molecular Recognition and Spectroscopic Properties of Cyclobis(paraquat-p-anthracene)

WANG Wei, SHAO Shi-Qun, ZHOU Hui, TENG Qi-Wen   

  1. Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China; College of Biology &Environment Engineering, Zhejiang Shuren University, Hangzhou 310015, P. R. China
  • Received:2008-04-30 Revised:2008-06-10 Published:2008-09-10
  • Contact: TENG Qi-Wen E-mail:wushi@zju.edu.cn

摘要:

环双(对-蒽基-对草快)是一种新型的缺电子大环仿生主体, 分子识别是其最重要的应用之一. 考察主体对一系列客体分子如水、氨、醇及杂环等的识别能力, 用密度泛函理论(DFT)中的B3LYP/3-21G基组对主客体复合物的结构进行优化. 在B3LYP/6-31G(d)水平上进行单点能计算, 校正后得到复合物的结合能. 用B3LYP/3-21G方法计算13C和3He化学位移. 结果表明, 主体对客体分子的识别主要靠客体上的杂原子与主体上的氢原子之间的氢键进行. 复合物的稳定化能受氢键的数目和距离影响. 氢键的形成导致部分复合物LUMO与HOMO能隙增大, 同时导致与氢键相连的C—H键上C原子的化学位移向低场移动. 复合物的芳香性与其结合能的大小及结合方式有关. 主体的芳香性因其与客体之间的弱相互作用而提高, 但太强的相互作用及客体在主体空腔内都将影响主体的环电流, 从而削弱其芳香性.

关键词: 环双(对-蒽基-对草快), 分子识别, 化学位移, 芳香性

Abstract:

Cyclobis(paraquat-p-anthracene) is a novel electron-deficient macrocyclic host. One of the most important applications of the host is molecular recognition. The binding energies of the host to several guest molecules like water, ammonia, alcohol, and heterocycles were investigated. The structures of the host-guest complexes were optimized using DFT (density functional theory) at B3LYP/3-21G level. The energies of the complexes were calculated at B3LYP/6-31G(d) level. The binding energies of the complexes were obtained after the correction of basis set superposition error. The 13C and 3He chemical shifts of the complexes were calculated by the gauge-including atomic orbital (GIAO) method at B3LYP/3-21G level. It indicates that the host can bind the guest molecules via hydrogen bonds between the heteroatoms in the guest and hydrogen atoms in the host. The binding energies of the complexes were mainly affected by the number and distance of the hydrogen bonds. The energy gaps for some of the complexes were increased owing to the formation of the hydrogen bonds. At the same time, the chemical shifts of the carbon atoms on the C—H bonds connected with the hydrogen bonds in the complexes relative to those of the same carbon atoms in the host were transferred downfield. The aromaticities of the complexes were relevant to the binding energies and ways. The aromaticity of the host was increased by the weak interaction between the host and guest molecules. The cyclic current of the host was decreased, thus the aromaticity was lowered owing to too strong host-guest interaction and incorporation of the guest molecules inside the cavity of the host.

Key words: Cyclobis(paraquat-p-anthracene), Molecular recognition, Chemical shift, Aromaticity

MSC2000: 

  • O641