Aggregation-induced emission-active gold(I) complexes with multi-stimuli luminescence switching

A series of diisocyano-based dinuclear gold(I) complexes have been synthesized, differing only in the bridge linking the two (identical) arms. All of these complexes have been thoroughly characterized by NMR and IR spectroscopy and elemental analysis. The gold(I) complexes 1a, 1b and 1c all exhibit aggregation-induced emission (AIE) characteristics and mechanochromic behavior; their phosphorescence properties show reversible switchable off-on green luminescence in response to grinding. We have investigated the origins of these phenomena by spectroscopy, phosphorescence quantum yields and X-ray powder diffraction. From the experimental data, we conclude that the changing of multiple intermolecular C-H center dot center dot center dot F, C center dot center dot center dot F, weak pi-pi interactions and the formation of aurophilic interactions are critical elements that determine the AIE-active and switchable mechanochromic luminescence.