Novel pyridyl based azo-derivative for the selective and colorimetric detection of nickel(II).

Abstract A highly sensitive and selective pyridyl based colorimetric chemosensor (H 2 L) for the efficient detection of Ni 2 + has been reported. The synthesized chemosensor H 2 L is highly efficient in detecting Ni 2 + even in the presence of other metal ions that commonly co-exist with Ni 2 + . H 2 L also shows distinct color change from green to deep red visible under naked eye due to specific binding with Ni 2 + . This color change is due to formation of a new band at 510 nm upon gradual addition of Ni 2 + . The association constant has been found to be 1.27 × 10 5  M − 1 with limit of detection (LOD) of 8.3 × 10 − 7  M. Electronic structure of the H 2 L–Ni 2 + complex and sensing mechanism have been interpreted theoretically by DFT and TDDFT calculations.