A chromophoric switch based on pseudorotaxanes.

In a three-component system containing dibenzo-24-crown-8 (1), diamino-dibenzo-24-crown-8 (2), and 1,2-bis(4,4′-dipyridyl)ethane (32+), axle 32+ can shuttle between wheels 1 and 2 by acid-base control, accompanying color changes from yellow to red. This system could not only be taken as a chromophoric supramolecular switch, but also exhibit a function as INHIBIT logic gate. [ABSTRACT FROM AUTHOR]