Snap-Fit Assembly of Multicomponent Pt(II) Metallacages Enabling Through-Space Electron Transfer and Enhanced Photocatalysis

The rational design of heteroleptic metallacages from multiple ligands remains a significant challenge in supramolecular chemistry due to the tendency for thermodynamic mixtures and poorly defined assemblies. Herein, we demonstrate a snap-fit-inspired self-assembly strategy for the construction of heteroleptic platinum(II) cages containing three types of organic ligands. An asymmetric tetracarboxylate ligand acts as a multifaceted connector, guiding the two distinct tetrapyridyl panels to snap into place around the Pt(II) vertices, yielding a type of box-shaped metallacage with reduced constitutional symmetry. Spatial combination of electron-rich anthracene or dimethoxybenzene donors with electron-deficient perylene diimide acceptors within a single metallacage facilitates efficient through-space photoinduced electron transfer and charge separation. As a result, the metallacages promote the generation of superoxide radical anions and enable photocatalytic benzimidazole formation from o -phenylenediamine and aromatic aldehydes via a condensation–oxidative cyclization sequence. This snap-fit assembly concept provides a modular and programmable approach to multicomponent metallacages and enables deliberate control over intramolecular electronic communication for supramolecular photocatalysis.