Systematic rim cyano functionalization of pillar[5]arene and corresponding host−guest property varieties

Synthetic investigation of the systematic replacement of alkoxy groups in pillar[5]arene by cyano ones was carried out. 2nCN-pillar[5]arenes (n = 1, 2, 3, 4 or 5) bearing different numbers of cyano functions on their rims were successfully prepared for the first time. Single-crystal X-ray diffraction studies showed that the nCN-pillar[5]arenes had unique conformations in the solid states. Besides, host–guest property studies of those nCN-pillar[5]arenes and 1,4-dicyanobutane showed the functionization number-related host–guest interaction varieties.