Highly Sensitive and Selective Fluorescent Sensor for Zinc Ion Based on a New Diarylethene with a Thiocarbamide Unit

A new photochromic diarylethene has been synthesized by using thiocarbamide as a functional group and perfluordiarylethene as photoswitching trigger via a Salicylidene Schiff base linkage. The diarylethene could he used as a multicontrollable fluorescence switch when triggered by base/acid, light, and metal ions. The results showed that the absorption and fluorescence characteristics of the diarylethene exhibited sequence-dependent responses through efficient interaction of specific salicylidene Schiff base-linked thiocarbamide unit with tetrabutylammonium hydroxide/trifluoroacetic acid and photoirradiation. Moreover, the diarylethene was highly selective toward Zn2+ ion with obvious fluorescence change from light blue to bright yellow in acetonitrile. The deprotonated form of the diarylethene had typical photochromism, but it showed an irreversible photocyclization reaction after binding with Zn2+. Finally, two logic circuits were constructed by using the fluorescence intensity as the output signal with the inputs of the combinational stimuli of light and chemical species.