3D Au–Ag heterometallic supramolecular cage: Triplet capture by heavy atom effect

The synthesis of a new 3D metallo-cage is obtained by means of the self-assembly reaction between the gold derivative [(triphos)(AuC6F4py)3] (triphos = 1,1,1-tris(diphenylphosphanylmethyl)ethane) and AgOTf in a 2:3 ratio. Several spectroscopic and spectrofluorimetric techniques and mass spectrometry have been used for the characterization of the supramolecule. MM calculations have been also important in order to optimize the geometry of the structure and postulate its ability to act as host in molecular recognition processes by means of its empty inner cavity. Changes on the emission spectra of the guest molecules naphthalene, methylsalicylate and 8-hydroxyquinoline showed the establishment of interactions between these molecules and the cage. A 1:2 cage:naphthalene adduct has been obtained while a 2:3 ratio has been observed for methylsalicylate and 8-hydroxyquinoline. stingly, the large number of metal atoms of the host has been observed to induce intersystem crossing of the organic molecules. Emission spectra at 77 K together with lifetime measurements are a definitive proof for the assignment of the triplet origin for the observed guest luminescence when trapped by the host.