Dicyanovinylcoumarin as a turn-on fluorescent sensor for cyanide ion

Dicyanovinylcoumarin chemosensors (4a, 4b and 4c) were designed and synthesized by the Knoevenagel condensation reaction. The electronic absorption and emission spectra of the dicyanovinylcoumarin isomers exhibited red shifted absorption and less emission as compared to their precursor's coumarin aldehydes. The sensing behavior of dicyanovinylcoumarin isomers were studied for different anions. In these dicyanovinylcoumarin isomers, the 7-substituted isomer shows high selectivity towards CN- in the presence of other F-, Cl-, Br-, I-, ClO4-, HSO4- and NO(2)(-)ions. The effect of CN- on the structure of dicyanovinylcoumarin isomer was studied by performing DFT calculations. The theoretical calculations show strong agreement with the experimental results. The detection limit for CN- were found to be 1.14 x 10(-8)M for 7-substitued dicyanovinylcoumarin isomer 4b. (C) 2017 Elsevier B.V. All rights reserved.