| Functional supramolecular assembly is always one of the most focused research realms in supramolecular chemistry since the birth of this newly-developed interdisciplinary science.Functional supramolecular assemblies are constructed by macrocyclic host molecules and guest molecules through non-covalent interactions.Due to non-covalent interactions usually exhibit diverse stimulus responsiveness to external stimulus,functional supramolecular assemblies always show potential practical applications in many fields such as drug delivery,biological probes,and molecular machines.Therefore,the development of new functional supramolecular assemblies have great research significance.Pillar[n]arene as a novel generation of macrocyclic hosts have attracted increasingly attention and made great progress since the first reported in 2008.Due to it has highly rigid cylindrical structure and electron-rich cavities,various novel inclusion complexes with different guests were constructed by pillar[n]arenes.Therefore,pillar[n]arenes have great research values and broad applications in many fields.On account of the outstanding potential applications of functional supramolecular assemblies and unique host–guest properties properties of pillar[n]arene,this dissertation focused our research on constructed pillar[5]arenes based functional supramolecular assemblies.The content of this dissertation mainly studied the following subjects:In the first part,the host-guest interaction and acid/base controllable properties between pyridine and Me P5A were investigated.On the basis of that,a ethylene glycol bridged pyridine and pillar[5]arene based mechanically selflocked pseudo[1]rotaxane2-1 was synthesized.Further more,Me P5A unit of pseudo[1]rotaxane 2-1 could shuttle between ethylene glycol chain and pyridine unit as an acid/base-controllable molecular shuttle.More over,DOSY experiments indicated that pseudo[1]rotaxane 2-1 performed as selflocked-monomer in low concentration(10.00 m M)and interlocked-dimer(100.0m M)in high concentration.After addition of TFA to concentrated solution of interlocked-dimer 2-2,it could changed from shrinking state to extension state like a molecular muscle.This system provides a new strategy for the construction of controllable rotaxane-type molecular machines.It also provides a basis for further construction of supramolecular logic gates.In the second part,a new pseudo[2]rotaxane was constructed by using host and guest interaction between 5,5’-dimethoxy-2,2’-bipyridine and Et P5A.This pseudo[2]rotaxane could be reversiblely regulated by the addition of acid/base.Firstly,we investigated the host-guest complex formed by 5,5’-dimethoxy-2,2’-bipyridine and Et P5A through ~1H NMR and mass spectrometry,indicating that the host-guest assembly between 5,5’-dimethoxy-2,2’-bipyridine and Et P5A could be easily regulated by the addition of acid/base.Then the host-guest assembly system was used to construct supramolecular logic gates in the presence of a linear molecules G1.The experimental results show that after the addition of acid,5,5’-dimethoxy-2,2’-bipyridine entered into the cavity of Et P5A.Continue adding base to this system,5,5’-dimethoxy-2,2’-bipyridine moved out form the cavity of Et P5A and G1 entered into the cavity of Et P5A instead.This system provides a good example for the construction of simple and efficient supramolecular logic gate and has potential application value in the field of information storage.Overall,in this dissertation,we constructed two functional supramolecular assemblies based on pillar[5]arene,an acid/base-controllable molecular shuttle and an acid/base-controllable logic gate.All of them provided meaningful reference for the practically constructed functional molecular machines based on pillararenes. |
