Synthesis and characteristics of a novel pseudorotaxane with the diarylethene as the functional stopper

The synthesis and characteristics of a novel pseudorotaxane formed by the diarylethene as the functional stopper, the CB[6] (cucurbit[6]uril) as the macrocycle and diprotonated diaminobutane as the ‘string’ were reported. The pseudorotaxane exhibited good photochromic properties and could be alternate between colorless ring-open and colored ring-closed forms by alternative irradiation with UV light of 254 nm and 365 nm because of the functional diarylethene stopper. The CB[6] bead was localized on aliphatic chain to combine N+ of the diprotonated diaminobutane by non-covalent bonds. The molar ratio of CB[6] to the ‘string’ was 1:1. This character will make it potential for use in the construction of the prototype of molecular machines.