Acrylonitrile Embeded Benz(Imida/Thia)Zole Based Chemodosimeter for Cyanide Ions

Abstract

Two novel chemodosimeters(Z)-2-(1H-benzo[d]imidazol-2-yl)-3-(4-(6,11-dioxo-5a,6,11,11a-tetrahydro-1H-anthra[1,2-d]imidazol-2-yl)phenyl)acrylonitrile (Probe 3) and (2Z,2'Z)-3,3'-(1,4-phenylene)bis(2-(3H-1l4-benzo[d]thiazol-2-yl)acrylonitrile) (Probe 5) were synthesized for cyanide anion detection via colorimetric and fluorometric approaches. Probe 3 displayed red shift in absorption spectrum from 415 to 466 nm and near infrared emission at 610 nm in presence of cyanide anion in aqueous acetonitrile solvent system. The probe 3 displayed colour change from yellow to reddish orange in presence of cyanide anion. The probe 3 showed very low detection limit of 2.2 × 10-9 M. On the other hand, probe 5 exhibited red shift in absorption from 385 to 584 nm and quenching in emission at 490 nm. The presence of cyanide anion changes colour of probe 5 from yellow to purple. The probe 5 shows very low detection limit of 3.5 × 10-7 M. Therefore, both probe 3 and probe 5 shows chromo and fluorogenic response towards cyanide anion in aqueous acetonitrile medium. Both probes contains nitrile-vinyl group as a reorganisation unit and their electron withdrawing properties creating electron deficient site allow nucleophilic attack by cyanide anion revealing intramolecular charge transfer.