Binding modes of cucurbit[6]uril and cucurbit[7]uril with a tetracationic bis(viologen) guest

作者：Yuan Lina; Wang Ruibing; Macartney Donal H^*

来源：Journal of Organic Chemistry, 2007, 72(12): 4539-4542.

DOI：10.1021/jo070358e

Binding behaviors of two cucurbit[n]urils (CB[n]) hosts with the [CH(3)bpy(CH2)(6)bpyCH(3)](4+) (bpy = 4,4'-bipyridinium) guest were investigated by H-1 NMR and MALDI-TOF-MS experiments. While the CB[6] and CB[7] form [2]pseudorotaxanes with the host located over the hexamethylene chain of the guest, only the CB[7] forms a [3]pseudorotaxane with both host molecules residing over the bipyridinium groups. The initial CB[7] host vacates the inclusion of the hexamethylene chain as a result of the electrostatic and steric repulsions that would arise in simultaneous binding of adjacent aliphatic and aromatic portions of the guest.

• 出版日期2007-6-8