Reversible disassembly of metallasupramolecular structures mediated by a metastable-state photoacidElectronic supplementary information (ESI) available: Containing synthetic procedures and experimental details. See DOI: 10.1039/c8sc01108g

The addition of a metastable-state photoacid to solutions containing metal-ligand assemblies renders the systems light responsive. Upon irradiation, proton transfer from the photoacid to the ligand is observed, resulting in disassembly of the metallasupramolecular structure. In the dark, the process is fully reversed. Light-induced switching was demonstrated for six different metal-ligand assemblies containing Pd II , Pt II or Ru II complexes and bridging polypyridyl ligands. The methodology allows liberating guest molecules with light. Only stable in the dark: when mixed with a metastable-state photoacid, metallasupramolecular structures become light sensitive. The photo-induced disassembly of the structures is reversed when the light is switched off.