From {Au^I···Au^I}‑Coupled Cages to the Cage-Built 2‑D {Au^I···Au^I} Arrays: Au^I···Au^I Bonding Interaction Driven Self-Assembly and Their Ag^I Sensing and Photo-Switchable Behavior

Metal–metal bonding interactions have been used to generate a number of unique supramolecular assemblies with fascinating functions. We presented here a new class of gold­(I)-containing metallosupramolecular cages and cage-built two-dimensional (2-D) arrays of {Au₈L₂}_n (n = 1 or ∞, L = tetrakis-dithiocarbamato-calix[4]­arene, TDCC), 1–3, which are constructed from the self-assembly of deep-cavitand calix[4]­arene-based supramolecular cages consisting of octanuclear Au­(I) motifs. Synchrotron radiation X-ray diffraction structural analyses of 1–3 revealed their quadruple-stranded helicate dimeric cage structure and the presence of 2-D arrays of cages linked together by inter- and intramolecular Au^I···Au^I interactions. Electronic absorption and emission studies of complexes 1–3 indicated the occurrence of a programmable self-assembly process in a concentration-dependent stepwise manner with the links built via aurophilic interactions. These novel gold­(I) supramolecular cages exhibited green phosphorescence and have been shown to serve as highly selective proof-of-concept luminescent sensors toward Ag^I cation among various competitive transition-metal ions.