Benzobis(imidazolium) salts as templates for the self-assembly of starburst [24]pseudorotaxanes and their corresponding carbene-based classic [22]pseudorotaxanes

Abstract

Benzobis(imidazolium) salts ([BBI-H₂-R₄]²⁺, R = alkyl, aryl) interact with crown ethers through a combination of hydrogen bonds, ion–dipole, and π–π stacking interactions to form starburst [2₄]pseudo-rotaxanes. This new recognition motif allows the extension of four side-arms directly from the cavity of the crown ether, thus positioning the wheel component in a straddled orientation onto the axle, while their carbene-based derivatives show the classical shape of regular [2₂]pseudorotaxanes.