Pseudorotaxane type host–guest complex of a secondary ammonium salt and oxacalixcrown with the polyether linker as short as five ethylene glycol units was created. While an axle containing both ammonium and carbamate stations was installed in an oxacalixcrown-6-based [2]rotaxane through a threading-followed-by-stoppering approach, translocation of the oxacalixcrown-6 component of the [2]rotaxane from the secondary ammonium station to the carbamate station of the thread was achieved through blocking the amino moiety with a bulky Boc group.

An improved partial oxidation of 1,4-dimethoxypillar[5]arene (DMP[5]) was described, through which selected pillar[n]arene[5−n]quinones, such as pillar[4]arene[1]quinone, pillar[3]arene[2]quinone, pillar[2]arene[3]quinone and pillar[1]arene[4]quinone, were synthesized by manipulating the ratio of oxidative reagent (NH₄)₂[Ce(NO₃)₆] to DMP[5].

1,8-Dioxyanthracene-based bisarylene crown ethers, composed of ethylene glycol chains and aromatic moieties, have been synthesized. Complexation studies revealed that these crown ethers could form 1:1 complexes with methyl viologen dication (N,N′-dimethyl-4,4′-bipyridinium dication; MV²⁺) in a mixed solvent of CDCl₃ and CD₃CN (1:1 v/v) with association constants in a range of (1.2 ± 0.1) × 10³ M^–1 to (1.6 ± 0.2) × 10⁴ M^–1. The structure of the complex and the strength of the π-donor/π-acceptor interactions between the 1,8-dioxyanthracene planes and the pyridinium rings of MV²⁺ are highly dependent on the length of the polyether chains of the ethers. Structural analysis showed that the tetraethylene glycol-derived bis-1,8-dioxyanthracene-based crown ether 9 forms a U-shaped host-guest complex with MV²⁺ by inserting the coplanar pyridinium rings of MV²⁺ between the two parallel oriented 1,8-dioxyanthracene units of 9, which is driven predominantly by π-donor/π-acceptor interactions. The pentaethylene glycol-derived bis-1,8-dioxyanthracene-based crown ether 10, however, adopts a crescent-shaped conformation in complex 10⊃MV²⁺ with the MV²⁺ guest being encapsulated by the polyether chains, propelled mainly by the hydrogen-bonding interactions between the hydrogen atoms of MV²⁺ and the oxygen atoms of the polyether chains of 10. Similarly, the hexaethylene glycol-derived bis-1,8-dioxyanthracene-based crown ether 11 forms a complex with MV²⁺. However, only weak π-donor/π-acceptor interactions between the aromatic groups of the mixed bisarylene crown ethers 12 and 13, and MV²⁺ were observed, and construction of tetracationic cyclophane [CBPQT⁴⁺] and crown ether 13 based [2]catenane 15 was achieved through supramolecular interactions between the [CBPQT⁴⁺] ring and naphtho unit in the crown ether.