Synthesis of a symmetrical tetrasubstituted cucurbit[6]uril and its host-guest inclusion complex with 2,2′-bipyridine

Since the structure of the first cucurbituril, a cyclic oligomer of 6 units of glycoluril linked by 12 methylene bridges was determined by Freeman et al. in 19811,2], considerable interest has emerged inspired by this new receptor. The receptor properties have been examined in a variety of ways such as polyrotaxanes, molecular neck-laces, rotaxane dendrimers, cyclo-addition reactions which occur more rapidly inside the cavity, and the treatment of effluent from the dye industry2—12]. Almost…