Formation of a series of stable pillar[5]arene-based pseudo[1]-rotaxanes and their [1]rotaxanes in the crystal state

A series of mono-amide-functionalized pillar[5]arenes with different lengths of N-ω-aminoalkyl groups as the side chain on the rim were designed and synthesized, which all formed pseudo[1]rotaxanes in the crystal state. And these pseudo[1]rotaxanes could be transformed into [1]rotaxanes or open forms in the crystal state. In addition, they were also studied in solution by (1)H NMR spectroscopy.