Chiral Assemblies of Planar and Achiral meta-Arylene Ethynylene Macrocycles Induced by Saccharide Recognition

We created chiral assemblies of planar and achiral macrocycles by saccharide recognition. To achieve this, we synthesized stackable meta-arylene ethynylene macrocycles consisting of pyridine-acetylene-phenol and pyridine-acetylene-aniline units. ¹H NMR, absorption, and fluorescence emission spectroscopy indicated that these macrocycles formed 1:1 and 2:1 complexes with lipophilic alkyl glycosides. The 2:1 complex of the pyridine-acetylene-phenol macrocycle showed induced circular dichroism (ICD) bands, meaning that two achiral macrocycles are arranged in an asymmetrically twisted manner. CD spectroscopy revealed that the helical sense was affected by the chirality of guest saccharides. On the other hand, strong CD bands were observed after solid-liquid extraction of native saccharides into lipophilic solvents using the pyridine-acetylene-aniline macrocycle.