Synthesis of novel 3-hydroxy-2-naphthoic hydrazones as selective chemosensors for cyanide ions.

The development of an effective and selective chemosensor for CN ions has become the need of the hour due to their hazardous impact on the environment and humans. Herein, we report the synthesis of two novel chemosensors, IF-1 and IF-2 based on 3-hydroxy-2-naphthohydrazide and aldehyde derivatives that have shown selective sensing of CN ions. IF-2 exhibited exclusive binding with CN ions that is further confirmed by the binding constant value of 4.77 × 10 M with a low detection limit (8.2 μM). The chemosensory potential is attributed to deprotonation of the labile Schiff base center by CN ions that results in a color change from colorless to yellow as visible by the naked eye. Accompanying this, a DFT study was also performed in order to find the interaction between the sensor (IF-1) and its ions (F). A notable charge transfer from 3-hydroxy-2-naphthamide to 2,4-di--butyl-6-methylphenol, was indicated by the FMO analysis. The QTAIM analysis revealed that in the complex compound, the strongest pure hydrogen-hydrogen bonding was observed between H53 and H58, indicated by a value of +0.017807. Due to its selective response, IF-2 can be successfully used for making test strips for the detection of CN ions.