Structural controls on catenane co-conformational dynamics: the interplay of ring size, rigidity, and curvature.

We report in this work the complex interplay of ring size, structural rigidity, and curvature of interlocked macrocycles on the co-conformational dynamics of copper(I) catenane complexes. Three series of copper(I) catenanes that incorporate isomeric catechol, resorcinol, and hydroquinone linkers, alongside flexible aliphatic segments of increasing length, were synthesised and characterised. Scrambling experiments revealed that thermodynamically, all the catenanes follow the same increasing trend in stability when the ring-size decreases due to the reinforced non-covalent interactions. Yet, distinct, linker-dependent kinetic behaviours were observed for the three catenane series, which can be explained by the curvature and rigid-to-flexible proportion of the macrocycles. These insights establish important design principles for functional metal catenanes, introducing unprecedented mechanical interlocking features to the field of coordination chemistry.