| Macrocyclic chemistry is one of the major topics in supramolecular chemistry. Crown ethers,cyclodextrins, calixarenes and cucurbiturils are the four generations of macrocyclic hosts of supramolecular chemistry. In2008, a novel host molecule, named as pillararene, was synthesized. It has rigid and symmetric pillar structure and shows fascinating host-guest properties which have been applied in different areas. In this dissertation, we investigate the preparation, functionalization, host-guest properties of pillararenes and their applications in supramolecular polymers.In the first part, DIBpillar[n]arenes (n=5,6) were synthesized. They showed different host-guest properties with n-octyltriethyl ammonium hexafluorophosphate (G) due to their different cavity sizes. DIBPillar[5]arene showed no complexation with G while DIBpillar[6]arene formed a1:1complex with G with an association constant of334(±24) M-1in chloroform. In this chapter, the first pillar[6]arene crystal structure and the first investigation of the host-guest chemistry of pillar[6] arenes were reported.In the second part,1,4-di(n-propoxy)pillar[5] arene (P5),1,4-di(n-propoxy)pillar[6]arene (P6) and1,4-di(n-propoxy)pillar[7]arene (P7) were synthesized from the condensation of1,4-di(n-propoxy)-2,5-bis(methoxymethyl)benzene using p-toluenesulfonic acid as the catalyst in dichloromethane. They were characterized by1H NMR,13C NMR and mass spectrometry. They had different1H NMR spectra but similar13C NMR spectra. The diameter of the internal cavity of P5is～4.7A, similar to those of cucurbit[6]uril (～5.8A) and α-cyclodextrin (～4.7A). The diameter of the internal cavity of P6is～6.7A, similar to those of cucurbit[7]uril (～7.3A) and β-cyclodextrin (～6.0A). The diameter of the internal cavity of P7is～8.7A, similar to those of cucurbit[8]uril (～8.8A) and y-cyclodextrin (～7.5A). The host-guest binding properties of them were investigated with n-octyltriethyl ammonium hexafluorophosphate (G) as a model guest. P6showed complexation with G while weak complexation was observed between G and P5, but no complexation occurred between P7and G.In the third part, we demonstrated that n-octylethyl ammonium hexafluorophosphate (G) can thread through the cavity of1,4-dimethoxypillar[5]arene to form a [2]pseudorotaxane with a binding constant of1.09(±0.31)×103M-1in chloroform. The formation of this threaded structure has been confirmed by proton NMR spectroscopy, electrospray ionization mass spectrometry, and X-ray single crystal analysis. The complexation between1,4-dimethoxypillar[5]arene and G in chloroform can be switched off by adding Cl-. For comparison, the complexation between1,4-di(n-propoxy)pillar[5]arene and G has also been investigated.In the forth part, a pillar[4]arene[1]quinone and a difunctionalized pillar[5]arene have been synthesized by partial oxidation. The difunctionalized pillar[5]arene can complex n-octylethyl ammonium hexafluorophosphate with a threaded geometry in chloroform while the pillar[4]arene[1]quinone can not.In the fifth part, a pillar[5]arene[1]quinone (DPP5A1Q) and a difunctionalized pillar[6] arene (5DP1HQP6) were synthesized. Their applications in host-guest chemistry were investigated by using1-adamantane ammonium tetrakis[3,5-bis(trifluoromethyl)-phenyl]borate (3), which had a weakly coordinating counteranion, as a model guest. These hosts showed different binding affinities for3with different association constants:2.00(±0.63)×104M-1for DPP6=)3,2.44(±1.44)×103M-1for DPP5A1Q(?)3, and3.33(±0.99)×104M-1for5DP1HQP6(?)3.In the sixth part, an AB-type heteroditopic monomer was prepared by incorporating a dialkylammonium salt into a copillar[5]arene prepared from co-oligomerization of1-(10-bromodecyloxy)-4-methoxybenzene and1,4-dimethoxybenzene. Based on the self-assembly of this new monomer in chloroform, a linear supramolecular polymer formed. The formation of the supramolecular polymer was characterized by various techniques including1H NMR, NOESY, DOSY, specific viscosity and SEM. This supramolecular polymer had anion-responsiveness, since the self-assembly of the monomer could be destroyed by the addition of chloride anion. This study provided an efficient and convenient strategy to control the formation of supramolecular polymers. |
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