Photophysics of supramolecular binary stacks consisting of electron-rich trinuclear Au(I) complexes and organic electrophiles

Two nucleophilic trinuclear Au(I) ring complexes, Au3((p-tolyl)N = C(OEt))3, 1, and Au3(μ-C2,N3-bzim)3, 2, form sandwich adducts with organic Lewis acids (C6F6 and C10F8) and electron acceptors (tetracyanoquinodimethane, TCNQ), a neutral polyfunctional inorganic Lewis acid (Hg3(o-C6F4)3), and naked heavy metal cations (Tl+ and Ag+). Fascinating photophysical properties are associated with the adducts formed, including external heavy-atom effect leading to room-temperature phosphorescence of aromatic molecules, quenching of luminescence upon exposure to organic vapors, and sensitization of metal-centered emissions in supramolecular stacks with luminescence thermochromism. Intermolecular interactions, including M-M bonding and π acid-base interactions, play the major role in influencing the luminescence properties.