Design, synthesis and characterization of gold(I) compounds with aggregation-induced emission and reversible mechanochromism characteristics

Abstract

Two gold (I) complexes 1 and 2 were designed, synthesized and structurally characterized by NMR, IR as well as elemental analysis. Fluorescence studies show that the two compounds exhibit very weak photoluminescence in pure organic solvents (dimethylsulfoxide or N,N-dimethyl formamide), enhanced fluorescences are observed after the addition of water, which indicate that the aggregation-induced emission (AIE) characteristics of these complexes. The solid-state fluorescence of complexes 1 and 2 can be significantly increased by grinding the solid samples. The recovery of the fluorescence intensity of these ground powders was detected after exposure the samples to organic solvent vapors. This phenomenon suggested the reversible mechanochromism behaviors of comounds 1 and 2. The powder X-ray diffracton (XRD) results displayed the morphology transition between the crystalline and amorphous states before and after the grinding of the sample. The AIE and reversible mechanochromism characteristics of complexes 1 and 2 made them can be potentially used for "smart" materials.