Rate-determining step in the self-assembly process of supramolecular coordination capsules

An in-depth understanding of the self-assembly process at the molecular level is crucial in both biological and materials science fields. However, such research is scarce due to the difficulty in monitoring a great deal of fragmentary species that are transiently produced in the process. We present a novel method for investigating the self-assembly process of supramolecular coordination assemblies by following the time variation of the average composition of the fragmentary species, which was indirectly determined by spectroscopy. With this method, we found that the final stage is the rate-determining step of the self-assembly of an octahedron-shaped coordination capsule, and that the relative energy barrier of each step is controllable by modifying the chemical structure of the building blocks.