Host–Guest chemistry based on solid-state pillar[n]arenes

Pillar[n]arenes, which were first reported by our group in 2008, are a new type of pillar-shaped host molecule in host–guest chemistry with versatile and unique host–guest behaviors. Host–guest complexation is mostly investigated in solution systems, where both the host and guest molecules are normally dissolved in solvent. Compared with normal host–guest complexation in solvents, solid-state host–guest complexation can offer the following advantages and characteristics: (i) Cavity-size dependent host–guest complexation, (ii) efficient host–guest complexation, and (iii) easy host–guest complex isolation and solid-state pillar[n]arene reuse. In this review, we discuss the recent development of solid-state host–guest complexation using crystalline pillar[n]arenes, two or three-dimensional networks containing pillar[n]arenes, including hydrogen-bonded organic frameworks (HOFs), and metal–organic frameworks (MOFs), pillar[n]arene-assembled surfaces, and solid-state organic polymers containing pillar[n]arenes.