A parallelogram metallomacrocycle bearing self-catenation and its derivative supramolecular isomerism.

Macrocycle-based architectures are of importance in synthetic chemistry. Here, a novel parallelogram metallomacrocycle Fe2(LA)2 with reversible structural transformation was designed and synthesized. The template-free metalla[2]catenane [Fe2(LA)2]2 could be obtained by changing the concentration and has been monitored on the basis of NMR analysis. By redesigning the metallo-ligand, a catenane-like intersected parallelogram assembly with two shape-persistent supramolecular isomers was achieved. This work develops the field of terpyridine-based macrocycle system research and is valuable for obtaining other types of supramolecular isomerism.