Anion binding in (arene)ruthenium(II)-based hosts

Asymmetric ruthenium(II) complexes of a flexible aminomethylpyridine derivative exhibit diastereotopic ligand methylene protons, as measured by NMR spectroscopy; binding of external anions renders these protons equivalent possibly by increasing dynamically averaged symmetry; the amount of anion needed to raise average symmetry correlates to the anion binding constant.