A Catenane Assembled through a Single Charge‐Assisted Halogen Bond

Interlocked molecules have captured chemists’ imagination owing to their nontrivial topology and the promise of their potential nanotechnological uses as molecular machines[1] and in chemical sensor applications.[2] The synthesis of such sophisticated architectures is a challenge, and as a consequence this has necessitated the implementation of imaginative cation,[3] anion,[4] and neutral[5] templation methodologies, which use a combination of complementary Lewis acid–base, electrostatic, and hydrogen-bonding interactions for component assembly. Halogen bonding (XB) is the attractive highly directional, noncovalent interaction between an electron-deficient halogen atom and a Lewis base.[6] The scope of XB in solid-state crystal engineering has been intensively explored for a number of years,[7] however, in spite of the complementary analogy to ubiquitous hydrogen bonding, it is only in recent times that investigations into the application of solution-phase XB interactions to molecular recognition processes, self-assembly, and catalysis have resulted in this field developing rapidly.[8] Indeed, in conjunction with anion templation, we have used XB to assemble interpenetrated and interlocked molecular frameworks.[8b–d]