An ionic liquid-modified diarylethene: Synthesis, properties and sensing cyanide ions.

An ionic liquid-modified diarylethene was synthesized and characterized. Its photochromic properties in a variety of solutions were studied. Compared to the neutral diarylethene, the closed-ring isomer of the ionic liquid-modified diarylethene exhibits obvious solvent-dependence. The closed-ring isomer showed solvatochromism depending on the solvent dielectric constants. More importantly, a dual colorimetric cyanide sensor with high selectivity has been achieved based on this ionic liquid-modified diarylethene derivative. Both the open-ring and closed-ring isomers recognized the strongly nucleophilic cyanide by forming of C4-cyano adducts. This study provides a novel design strategy for the development of photochromic diarylethenes for the colorimetric recognition of CN-.