A quinazolin-based Schiff-base chemosensor for colorimetric detection of Ni 2+ and Zn 2+ ions and ' turn-on ' fluorometric detection of Zn 2+ ion.

Herein, we have reported a novel quinazolin-based Schiff base chemosensor ( E )-2-benzamido- N '-(1-(pyridin-2-yl)ethylidene)benzohydrazide (L). L has been designed, synthesised and characterised by 1 H-NMR, IR spectroscopy, ESI-MS spectrometry and theoretical studies. The receptor showed appreciable colorimetric λ max shift for both Ni 2+ and Zn 2+ ions and fluorometric " turn on " response in presence of only Zn 2+ ion. The Jobs plot analysis revealed that receptor forms 2 : 1 complex with both the ions Ni 2+ and Zn 2+ , further confirmed by ESI-MS analysis. The single crystal structure of L-Ni 2+ complex (1) has also been determined. The colorimetric detection limits were calculated to 7.9 nM and 7.5 nM respectively for Ni 2+ and Zn 2+ in methanol-Tris-HCl buffer medium (10 mM, pH 7.2, 1 : 1 v/v). The chemosensor L can be applied for the recovery of contaminated water samples.