Construction And Applications Of Rotaxanes Based On Pillar[5] Arene

The design and synthesis of various molecular machines based on supramolecular hosts have become a hot topic in supramolecular chemistry.The electron-rich cavity structure of pillar[5]arene is a good prerequisite for the study of host-guest chemistry.Based on it,various molecular machines are designed and synthesized,which are widely used in cell imaging,biosensor,ion channel and drug transportRotaxanes are mainly composed of one or more axial molecules and one or more macrocyclic molecules.Rotaxanes based on pillar[5]arene can recognize both cations and neutral molecules.The modified pillar[5]arenes can recognize anions and possess the special mechanical interlocking structure of rotaxanes,which expands its application scope.In this paper,a series of rotaxanes based on pillar[5]arene were designed and synthesized,and their catalytic ability and self-assembly performance for organic reactions were studied1.The[2]rotaxanes based on pillar[5]arene as the main component were synthesized by threading and capping" method.Firstly,the linear guest molecules were synthesized by the Click" reaction of 4-(propy1-2-alkyne-1-yloxy)benzaldehyde with different number of carbon chains containing azide unit.Then,it was "penetrated" into the cavity of pillar[5]arenes and the "stopper" was constructed by multi-component reaction to synthesize rotaxanes.In order to study the catalytic ability of Suzuki Miyaura coupling reaction,metal catalysts were prepared by coordination reaction of[2]rotaxanes based on pillar[5]arene and Pd(NO3)2.2‘Through the cycloaddition reaction between alkyne group and azide group,a longer chain linear guest molecule was designed and synthesized,and the[3]rotaxanes based on pillar[5]arene as the main body was synthesized by using the intermolecular force between it and pillar[5]arenes.Considering that the amino group and triazole group contained in the structure of[3]rotaxanes based on pillar[5]arene can be protonated,we tried to explore the self-assembly properties of[3]rotaxane based on pillar[5]arenes in water and its response to pH.3.Through mono substituted pillar[5]arene,the linear guest molecules were first"capped" at one end,and then the rotaxane compounds were synthesized by "thread capping method.By changing the length of alkyl chain in mono substituted pillar[5]arene,one end self-contained[1]rotaxanes can be synthesized,and the[1]/[2]composite rotaxanes based on pillar[5]arene can be synthesized by host-guest interaction with pillar[5]arene.At the same time,its self-assembly performance in solvent was also explored.