Host-guest complexes of a water soluble cucurbit[6]uril derivative with some dications of 1,ω-alkyldipyridines:~1H NMR and X-ray structures  

作　　者：XIAO Xin ZHANG YunQian ZHU QianJiang XUE SaiFeng TAO Zhu 

机构地区：[1]Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province,Guizhou University,Guiyang 550025,China [2]Institute of Applied Chemistry,Guizhou University,Guiyang 550025,China

出　　处：《Science China Chemistry》2009年第4期475-482,共8页中国科学（化学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 20662003 & 20767001);the International Collaborative Project of Guizhou Province (Grant No. 2007400108);the Science Technology Fund of Guizhou Province (Grant No. J-2008-2012);the Natural Science Youth Foundation of Guizhou University (Grant No. 2007-005)

摘　　要：Interactions between a symmetrical tetramethyl-substituted cucurbit[6]uril (host:TMeQ[6]) and 1,ω-alkylenedipyridine (ω = 2,4,6,8,10) dicationic guests were investigated using 1H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes,combined cavity and portal binding in TMeQ[6] were observed,and the length of the bridged alkylene was found to play an important role not only in balancing the overall hydrophilic/hydrophobic interaction between the host and the guest,but also in defining the structure of the resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy),TMeQ[6] includes a positively charged pyridine ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy),TMeQ[6] includes a positively charged pyridine ring of Bdpy,but the different competitive interactions in and between the related inclusion complexes could lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains,such as 1,6-hexamethylenedipyridine (Hdpy) or 1,8-octylenedipyridine (Odpy),a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic cavity and the outer portal dipoleion interactions. However,for 1,10-decatylenedipyridine (Ddpy),the two TMeQ[6] host molecules include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex.Interactions between a symmetrical tetramethyl-substituted cucurbit[6]uril (host: TMeQ[6]) and 1,ω-alkylenedipyridine (ω = 2, 4, 6, 8, 10) dicationic guests were investigated using 1H NMR spectroscopy and single crystal X-ray crystallography. In these inclusion complexes, combined cavity and portal binding in TMeQ[6] were observed, and the length of the bridged alkylene was found to play an important role not only in balancing the overall hydrophilic/hydrophobic interaction between the host and the guest, but also in defining the structure of the resulting inclusion complexes. For the guest 1,2-ethylenedipyridine (Edpy), TMeQ[6] includes a positively charged pyridine ring of Edpy to form an unsymmetrical inclusion complex; for the guest 1,4-butylenedipyridine (Bdpy), TMeQ[6] includes a positively charged pyridine ring of Bdpy, but the different competitive interactions in and between the related inclusion complexes could lead to a fast exchange between the hosts and guests. For the guests with longer bridge chains, such as 1,6-hexamethylenedipyridine (Hdpy) or 1,8-octylenedipyridine (Odpy), a stable pseudorotaxane inclusion complex is formed by combining the hydrophobic cavity and the outer portal dipole-ion interactions. However, for 1,10-decatylenedipyridine (Ddpy), the two TMeQ[6] host molecules include the two end pyridine rings of Ddpy and form a dumbbell inclusion complex.

关 键 词：SYMMETRICAL tetramethyl-substituted uril 1 ω-alkylenedipyridine (ω = 2 4 6 8 10) dicationic GUESTS HOST-GUEST complex 1H NMR spectroscopy single crystal X-ray CRYSTALLOGRAPHY 

分 类 号：O626[理学—有机化学]