An orange light emitting 'off–on-off' fluorogenic probe for consecutive detection of Al3+ ions and 2,4,6-trinitrophenol.

An orange light emitting 'off–on-off' fluorogenic probe for consecutive detection of Al3+ ions and 2,4,6-trinitrophenol having detection and quantification limit in the nM range. [Display omitted] • A fluorogenic sensor (HNMN) has been introduced to detect Al3+ ions and picric acid (PA). • A paper strips-based test kit has been fabricated to detect Al3+ ions and PA. • The LOD and LOQ values are found to be 8.6 nM and 28.4 nM respectively in the DMF medium. • Demonstrate a facile approach to design highly red-shifting fluorosensors from the non-fluorophore moieties. • Could be avoided false signaling during the detection of target analytes. A simple, orange light emitting 'off–on-off' fluorogenic sensor, (E)-4-(((2-hydroxy-4-nitrophenyl) imino) methyl) naphthalene-3-ol (HNMN), has been introduced for the successive recognition of Al3+ ions and 2, 4, 6-trinitrophenol respectively, utilizing the photoluminescence 'off–on-off' mechanism. A significant enhancement in the photoluminescence of HNMN is found at 558 nm, attributed to the chelation of Al3+ ions, resulting in a visible orange-colored photoluminescence under a handy 365 nm UV light illumination. Among the different tested nitroaromatic compounds (NACs), 2, 4, 6-trinitrophenol, namely picric acid (PA), selectively quenches the orange photoluminescence caused by Al3+ on the HNMN complex. The stoichiometric ratio for the complex formation between HNMN and aluminum ion is determined to be 1:1, with an estimated limit of detection (LOD) and quantification (LOQ) found to be 8.6 nM and 28.4 nM respectively in DMF medium. Different spectroscopic analyses have elucidated the mechanistic features of identifying Al3+ ions. A test kit–based experiment is performed with the HNMN- coated filter paper to detect Al3+ ions and PA sequentially & selectively. Based on the chemical inputs and optical output, we have framed the INHIBIT molecular logic circuit. The present report evokes a facile approach for the design and molecular development of highly red-shifting fluorosensors from the non-fluorophore moieties to avoid false signaling during the detection of target analytes. [ABSTRACT FROM AUTHOR]