A rigid-axle-based molecular rotaxane channel facilitates K + /Cl - co-transport across a lipid membrane.

Inspired by the design criteria of heteroditopic receptors for ion-pair binding, we herein describe a new strategy to construct a rotaxane transporter (RR[2]) for K + /Cl - co-transport. The use of a rigid axle improves the transport activity with an EC 50 value of 0.58 μM, presenting a significant step toward developing rotaxane artificial channels.