Structural Study of Triazole and Amide Containing Anion-Templated Pseudorotaxanes

The
ability of a range of halides and oxoanions to template pseudorotaxane
formation between an isophthalamide containing macrocycle and either
bis-triazole pyridinium or bis-amide pyridinium threading components
was investigated. Solution 1H NMR experiments reveal that
all of the studied anions (Cl–, Br–, I–, NO3–, HSO4–, OAc–, and BzO–) can template interpenetrated assemblies. The solid-state structures
of nine of the pseudorotaxanes were determined by single crystal X-ray
structural analysis. In the solid state, the oxoanions nitrate, acetate
and benzoate display much stronger hydrogen bonding with the macrocycle
and threading components than the halide anions. Conversely, aromatic
donor–acceptor contacts between the macrocycle and thread are
significantly longer in the oxoanion templated pseudorotaxanes, presumably
due to the greater steric demands of these larger templates.