Controlling the Complexity and Interconversion Mechanisms in Self-Assembled [Fe 2 L 3 ] 4+ Helicates and [Fe 4 L 6 ] 8+ Cages.

Self-assembled coordination cages and metal-organic frameworks have relied extensively on symmetric ligands in their formation. Here we have prepared a relatively simple system employing an unsymmetric ligand that results in two distinct self-assembled structures, a [Fe 2 L 3 ] 4+ helicate and a [Fe 4 L 6 ] 8+ cage composed of 10 interconverting diastereomers and their enantiomers. We show that the steric profile of the ligand controls the complexity, thermodynamics and kinetics of interconversion of the system.