A recyclable probe for highly selective and sensitive detection of cyanide anion in aqueous medium by fluorescent and colorimetric changes

In this work, a novel Schiff-Base (Q1) which based on 5-(4-nitrophenyl)-2-furan and naphtho[2,1-b]furan-2-carbohydrazide was designed to act efficiently in a chemodosimeter approach for the selective detection of cyanide in aqueous medium. The recognition progress occurred via deprotonating between the hydrazide moiety of Q1 and cyanide. When exposed Q1 to the low concentration solution of cyanide anion, there was a significant color change from yellow to orange in visible light and accompanied with a strong and broad red shift (from lambda(max-ab) = 400 nm to lambda(max-ab) = 468 nm) in the UV-vis absorption spectrum. Meanwhile, a dramatically decrease almost 4 times of the emission maximum of Q1 took place from 775 (a.u.) to 204 (a.u.), and the color of the solution changed from bright orange to dim red, which can be saw by naked-eyes under the UV lamp (365 nm). However, without any signal changes after the addition of other common anions, especially the basic anions such as F-, AcO-, H2PO4 and SCN-. Notably, this probe can serve as a recyclable component in sensing materials. The corresponding experiment proved that this probe can be repeated use above 10 times. (Scheme 1) On the basis of these observations and supporting mechanistic analyses, it is concluded that the recyclable probe Q1 must be a promising cyanide anion indicator that is attractive in terms of its selectivity, ease-of-use, rapid response (<3 s), and the low, naked eye discernible cyanide detection limit it, also it will be regarded as an environmental friendly material which can sensing cyanide anion in aqueous medium and making great contribution to the development of cyanide anion sensors. (C) 2016 Elsevier B.V. All rights reserved.