Being positive is not everything – experimental and computational studies on the selectivity of a self‐assembled, multiple redox‐state receptor that binds anions with up to picomolar affinities

The interaction of a redox-active trinuclear, self-assembled Ru metallomacrocycle with oxo-anions is reported and its affinity for these anions and halides in different oxidation states is calculated, revealing both high affinities (>109 M−1 for some guests) and high selectivities (a range of >107 M−1). Detailed quantum-based computational studies on the host in each of its oxidation states, revealed that it binds anion guests by a combination of non-covalent interactions, including charge-assisted hydrogen bonding and anion-π interactions.