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^-, NO ₃^-, 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.