From AuI···AuI-Coupled Cages to the Cage-Built 2-D AuI···AuI Arrays: AuI···AuI Bonding Interaction Driven Self-Assembly and Their AgI 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 Au8L2n (n = 1 or ∞, L = tetrakis-dithiocarbamato-calix4arene, TDCC), 1-3, which are constructed from the self-assembly of deep-cavitand calix4arene-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.