A unique benzimidazole-naphthalene hybrid molecule for independent detection of Zn2+ and N3 − ions: Experimental and theoretical investigations

Abstract

Single crystal X-ray structurally characterized benzimidazole-naphthalene hybrid (NABI) functions as a unique dual analyte sensor that can detect Zn2+ cation and N3 − anion independently. The NABI forms chelate with Zn2+ to inhibit internal charge transfer (ICT) and –CH[dbnd]N– isomerisation resulting chelation enhanced fluorescence (CHEF). On the other hand, the sensing of N3 − is based on formation of supramolecular H-bonded rigid assembly. The association constant of NABI for Zn2+ and N3 − ions are 19 × 104 M−1 and 11 × 102 M−1, respectively. Corresponding limit of detections (LOD) are 6.85 × 10−8 and 1.82 × 10−7 M, respectively. NABI efficiently detects intracellular Zn2+ and N3 − ions with no cytotoxicity on J774A.1cells under fluorescence microscope. DFT studies unlock underlying spectroscopic properties of free NABI and Zn2+/N3 − bound forms. © 2018 Elsevier B.V.