Study On The Host-guest Complexation Based On Water-soluble Pillar[n]arene

In 2008,pillar[5]arene was firstly reported by Ogoshi group.Compared with other macrocyclic hosts(Crown ether,cyclodextrin,calix[n]arene,cucurbit[n]uril),pillararene has a rigid and symmetrical structur e.Moreover,it is flexible to synthesis and modification.It has become a research field of supramolecular chemistry reserch.With the development of pillararene research,supramolecular chemists have introduced water-soluble groups into pillararenes to synthesize water-soluble pillararenes,which extended the host-guest chemistry of pillararenes into water and enriched the contents of pillararenes.Water-soluble pillararenes are receiving more and more attention from supramolecular researchers because of their unique and excellent host-guest properties.At present,five-and six-membered water-soluble pillararenes have recived extensivly attentions.Some groups have reported the synthesis and application of water-soluble pillararene with larger rings.It demonstrates that water-soluble pillararenes show great potentials in host-guest chemistry.In this thesis,we selected three water-soluble pillar[5]arene with different functional groups,and studied their complexation properties with water-soluble ionic compounds in water.The first part focuses on the study of the host-guest properties between water-soluble pillar[5]arene and imidazolium ionic liquids in w ater.In 2012,Ogoshi group reported a pillar[5]arene(1)with LCST(lower critical solution temperature)behaviour.We were found that the addition of different functionalized imidazolium ionic liquids G1-G8 to solutions can form 1:1 host-guest complexes.In addition,LCST b ehavior of water-soluble pillar[5]arene can be controlled by the additi on of guests.Due to the formation of 1/ionic liquid supramolecular complexes,higher cloud points were obtained.Supramolecular control over LCST behaviour was proved by temperature-dependent UV/vis and temperature-dependent NMR experiments.We also found that geometry of host-guest complexes is very important in LCST system controlled.In the second part,two water-soluble pillar[5]arene WP5 and AP 5 were uesd the hosts and triazole and sodium triazole were selected as the guests.A simple,selective host-guest system based on water-so luble pillar[5]arene was successfully established.Both triazole and sod ium triazole have host-guest interaction with WP5,and the complexati on constant of WP5 with triazole or sodium triazole are determined by IH NMR titration experiments respectively.Moreover,we have established a selective supramolecular system based on water-soluble pillar[5]arene.The positively charged water-soluble pillar[5]arene AP5 cann ot bind triazole.While cation-typewhile sodium triazole can be selectively complexed by AP5.