Twisted Cucurbit[14]uril

Simple Coordination Complexes of Cucurbit[n]urils with Metal Ions

“…The first known Q [5] is decamethylcucurbit [5]uril (Me 10 Q [5]), which was reported in 1992 [6]. The hostguest chemistry of the Q [5]s has received less attention than their larger homologs because of the limited size of the portals and the capacity of their cavities [7][8][9][10].…”

“…To the best of our knowledge, the first reported crystal structure is a Q [5]-based coordination complex with a molecular bowl confirmation by covering a barium ion on one portal of a decamethylcucurbit [5]uril molecule, and the "bowls" further construct a honeycomb-like supramolecular assembly through hydrogen bonding and ion-dipole interactions ( Fig. 2.1) [11].…”

“…The unsubstituted or substituted cucurbit [5]urils (Q [5] and SQ [5]s, respectively) are the smallest members or homologs in the Q[n] family. The first known Q [5] is decamethylcucurbit [5]uril (Me 10 Q [5]), which was reported in 1992 [6].…”

Oxidation of Cucurbituril and Its Analogues

“…CB [6]早在 1905 年就由德国化学家 Behrend 等合 成出来 [1] , 但直到 20 世纪 80 年代前后德国另一位学者 Freeman 和美国学者 Mock 等重新研究了 Behrend 等的 工作, 并用硫酸钙处理获得缩合产物与钙离子络合的水 合体, 再通过结构测定确定其缩合产物是由六个甘脲经 由亚甲基桥联的大环聚合物 CB [6] [2] . 迄今, 一系列 CB [6]的类似物, 如 CB [5], CB [7], CB [8], iCB [6], iCB [7], CB [10]和 tCB [14]等都已为世人所认知 [3][4][5][6][7][8] , 并应用于很 多方面 [9～11] .…”

“…理论上这三部分 都可以发生反应(或转化), 即腰位偕二次甲基 C-H 键 和桥联亚甲基 C-H 键的功能化; 脲羰基的还原或水解 (Scheme 1), 特别是酰胺一般易水解 [12] , 但葫芦脲的弧 形偕环结构使得其非常稳定, 能够耐受 370 ℃的高温 而不分解, 即使是 100℃的浓盐酸, CB [5], CB [6], CB [7] 也不分解 [4] . [19,20] .…”