Pillar[5]arene-based Self-included Compounds Applied To Molecular Machines And Dynamic Combinatorial Chemistry

Supramolecular chemistry is an interdisciplinary discipline involving modern chemistry,material science and life science and emerged with the discovery of new macrocycles.Following the reported macrocycles such as cyclophane,crown ether and cryptand,cyclodextrin,cucurbit[n]urils and calix[n]arene,pillar[n]arene has been intensively developed and applied as a new macrocylic host molecule,and also attracted more and more attention of supramolecular chemists around the world.The research related to macrocyclic chemistry such as pillararene has also been recently spotlighted with the attribution of the Nobel Prize of Chemistry awarded to three scientists for the development of molecular machines.Pillararene-based molecular machines lied mostly in [2]rotaxanes,and much less in [1]rotaxanes.Based on this background,we studied several useful pseudo[1]rotaxanes and synthesized a functionalized [1]rotaxane and an artificial receptor,then applied them in molecular machines and Dynamic Combinatorial Chemistry(DCC).The main contents was divided in three parts.In the first part,a novel pillar[5]arene-based pseudo[1]rotaxane and [1]rotaxane were synthesized.Their structures had been characterized by 1D and 2D NMR spectra,mass spectra and Density Functional Theory(DFT)calculations.Based on the catalytic property of a tertiary amine in the [1]rotaxane and along with the comparative experiments,we finally used it in the catalysis of the Knoevenagel reaction in chloroform,in which the model reaction between malononitrile and acetone had a second order reaction kinetics.We also concluded that the steric hindrance of pillar[5]arene had efficiently adjusted to the reaction.In the second part,two macrocycles named diethyl pillar[5]arene(DEP5A)and monoester-based copillar[5]arene were synthesized by a one-pot reaction.Based on the previously described methodology,we fabricated a new pillar[5]arene-based artificial receptor.On one hand,according to the job's plot method and NMR titration,we selected a dynamic combinatorial library(DCL)where some representative aldehydes and amines were studied and adjusted by DEP5 A in the DCLs of the imine formation in the presence of anisidine.On the other hand,we can use this artificial receptor to achieve the reverse selectivity of the same DCLs.Furthermore,we controlled the aliphatic imine formation in the cavity of pillar[5]arene and found the corresponding imines and hemiaminals by liquid chromatography electrospray ionization mass spectra(LC-ESI-MS).Finally we discussed a four-member-ring transition state that maybe finalized the imine formation by DFT calculation.In the third part,some new pillar[5]arene-based molecules were used to expand their application for this concept.?)A pillar[5]arene-based molecular spring was created.Such a molecule could move like a spring under different conditions by controlling the p H of the system which was monitored by 2D NMR spectra and mass spectra.DFT calculations revealed that the motion of this kind of spring could be adjusted by designing molecules that could decrease the hindrance of pillar[5]arene itself.?)a serie of pillar[5]arene-based pseudo[1]rotaxane-like chiral catalysts were synthesized and characterized by NMR spectra,Mass spectra,and these catalysts have great potential to catalyze enantioselectiviely an aldol reaction in a self-adaptive manner.