Water-soluble, multi-component disulfide cages showing a self-sorting behavior and cation sensing ability.

Complexation of metal ions by a ligand bearing a azobenzene linker yielded two types of complexes: an [M2L2]4+ metallocycle and an [M4L6]8+ tetrahedral cage, which can be further converted into libraries of mononuclear [M(L′/L′′)n]2+ species.

We previously reported novel fluorescent aromatic cages that are self-produced using a set of orthogonal dynamic covalent reactions, operating simultaneously in one-pot, to assemble up to 10 components through 12 reactions into a single cage-type structure. We now introduce N-functionalized amino acids as new building blocks that enable tuning the solubility and analysis of the resulting cages. A convenient divergent synthetic approach was developed to tether different side chains on the N-terminal of a cysteine-derived building block. Our studies show that this chemical functionalization does not prevent the subsequent self-assembly and effective formation of desired cages. While the originally described cages required 94% DMSO, the new ones bearing hydrophobic side chains were found soluble in organic solvents (up to 75% CHCl 3 ), and those grafted with hydrophilic side chains were soluble in water (up to 75% H 2 O). Fluorescence studies confirmed that despite cage functionalization the aggregation-induced emission properties of those architectures are retained. Thus, this work significantly expands the range of solvents in which these self-assembled cage compounds can be generated, which in turn should enable new applications, possibly as fluorescent sensors.

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