Host-guest complexation between simple pillar[5]arene and a new type of neutral guests

Abstract

ABSTRACT Pillar[5]arenes are a new type of supramolecular hosts constructed from hydroquinone and their derivatives linked by methylene units. Searching new host-guest interaction between pillar[5]arenes and neutral guests are thus great interesting. Here, four neutral guests (AA0, AA2, AA4 and AA6) with both amino and amide groups were prepared from phenol by two steps. The host-guest interactions between perethylated pillar[5]arene (EtP5) and guest molecules were investigated in detail by various technologies, including 1H NMR, 13C NMR, 2D NOESY NMR, MS analysis and DFT calculation. We found that the guests (AA4 and AA6) with longer alkyl chain can form a stable inclusion complex with EtP5 through C–H···O, N–H···O, C–H···N and C–H···π interactions while shorter guests (AA0 and AA2) could not.