Orthogonal Stimuli Trigger Self-Assembly and Phase Transfer of FeII4L4 Cages and Cargoes.

Two differently protected aldehydes, A and B, were demonstrated to deprotect selectively through the application of light and heat, respectively. In the presence of iron(II) and a triamine, two distinct FeII4L4 cages, 1 and 2, were thus observed to form from the deprotected A and B, respectively. The alkyl tails of B and 2 render them preferentially soluble in cyclopentane, whereas A and 1 remain in acetonitrile. The stimulus applied (either light or heat) thus determines the outcome of self-assembly and dictates whether the cage and its ferrocene cargo remain in acetonitrile, or transport into cyclopentane. Cage self-assembly and cargo transport between phases can in this fashion be programmed using orthogonal stimuli.