Formation of pseudo[3]rotaxanes containing calix-bis-crowns and secondary ammonium ions and their thermodynamic stabilities in a solution: preorganization by second macrocycle and nonallosteric behavior exhibited by large crown cavities

[摘要] This Letter describes the formation of pseudo[3]rotaxanes containing calix[4]-bis-crowns, exhibiting a 1,3-alternate conformation and large crown cavities, and secondary ammonium ions. The first and second association constants of pseudo[3]rotaxane formation are moderate (K-1 = 175, K-2 = 100 M-1) and are higher than that of the corresponding pseudo[2]rotaxane (K = 24 M-1), consisting of a calix[4]-monocrown and the same secondary ammonium ion. (C) 2013 Elsevier Ltd. All rights reserved.

[发布日期] 2013-12-11

[关键词] Rotaxane;Calixarene;Crown ether;Thermodynamic stability;Hydrogen bond