Reversible Mechanochromic Luminescence of [(C_6F_5Au)_2(μ-1,4-Diisocyanobenzene)]

摘要

Mechanochromism is the phenomenon of color change due to mechanical grinding or pressing of a solid sample, and the subsequent reversion to its original color through treatment such as heating or recrystallization. Photoluminescent compounds that possess mechanochromic properties in their solid-state emissions can provide unique recording or sensing materials that involve luminescence detection. Unfortunately, reports that describe such mechanochromic, photoluminescent compounds have been limited. Herein, we report the mechanochromic luminescence behavior of [(C6F_5Au_2(μ-1,4-diisocyanoben-zene)] (1)-the photoluminescence of the solid, upon grinding, undergoes a drastic change and, upon exposure to solvents or its vapor, is restored to its original color. Optical properties, powder X-ray diffraction (XRD), IR measurements, and X-ray crystallographic analysis strongly suggest that the mechanochromic property is attributable to changes in the molecular arrangement, rather than molecular structure, of the Au(I) complexes in the solid state.