Search

This article highlights the investigation of anion interactions and recognition abilities of naphthalene derivative, [(E)-1-(((4-nitrophenyl)imino)methyl)naphthalen-2-ol], (NIMO) by UV–visible spectroscopically and colorimetrically. NIMO shows selective recognition of F− ions colorimetrically, and a visual color change from yellow to pink is observed by the naked eye. The F− ions recognition is fully reversible in the presence of HSO4− ions. The limit of F− ions detection by NIMO could be possible down to 0.033 ppm-level. A paper strips-based test kit has been demonstrated to detect F− ions selectively by the naked eye, and a smartphone-based method for real sample analysis in the non-aqueous medium has also been demostrated. Spectroscopic behavior is well supported by pKa value calculation and DFT analysis, to find a correlation with receptor analyte interaction. The optical response of NIMO towards the accumulation of F− ions and, subsequently, HSO4− ions as chemical inputs provides an opportunity to construct INH and IMP molecular logic gates. [ABSTRACT FROM AUTHOR]

A julolidine‐coupled benzoxazole‐based fluorescent chemosensor (BPOZ) is designed and developed to investigate the different target analyte interactions spectroscopically. Based on the ′off‐on‐off′ photoluminescence mechanism, the as‐prepared BPOZ is used for sequentially detecting Zn2+ and HSO4− ions, respectively. The UV‐visible absorption and photoluminescence spectral behavior is intramolecular charge transfer (ICT) in nature. When Zn2+ ions bind with BPOZ, its fluorescence is significantly enhanced at 512 nm due to chelation‐enhanced fluorescence. A green color emission is also visible under 365 nm UV light exposure, which is also confirmed by the color chromaticity diagram. Chelation‐enhanced photoluminescence is also manifested in the lifetime decay analysis. Further, it is well supported by different spectroscopic techniques and DFT analysis. In the presence of HSO4− ions, photoluminescence of the Zn2+ chelated BPOZ complex is significantly reduced, rebirthing the free BPOZ. The detection limit of BPOZ for Zn2+ and Zn2+ chelated BPOZ complex towards detecting Zn2+ and HSO4− ions is established to be in the order of nM and μM range, respectively, in the solution phase. Among the various explosive nitroaromatic compounds, picric acid (PA) quenched the emission of the Zn2+ chelated BPOZ complex, and the quenching mechanism is found to be both static and dynamic in nature. Using these chemically prearranged inputs and optical outputs, two inputs, INHIBIT, and three inputs, combinational logic gates have been constructed. The BPOZ chemosensor and Zn2+ chelated BPOZ complex are also employed to map Zn2+ ions and PA in the living cell. The performance of the BPOZ chemosensor and Zn2+ chelated BPOZ complex toward Zn2+ ions and PA proved that it could be exploited as a signal tool for environmental and biological samples. [ABSTRACT FROM AUTHOR]

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]

• A Sulfone-based fluorogenic probe, ASSA, has been introduced for cascade detection of Zn2+ and PO 4 3− ions. • An instant green fluorescence is observed due to the chelation of Zn2+ ions with ASSA. • The chelation of Zn2+ ions with ASSA is in a 1:1 stoichiometric ratio with a binding constant of 2.6 × 105 M−1. • The detection limit of Zn2+and PO 4 3− ions is 16.65 nM and 0.134 μ M , respectively. • A handy paper strips-based has been fabricated to recognize Zn2+ ions. Detection of trace amounts of metal and non-metal ions is environmentally and biologically significant. In the present contribution, we have introduced a fluorogenic 4,4-diaminodiphenylsulphone-based probe, ASSA , which instantly detects Zn2+ions in its solid and liquid medium. With the implementation of Zn2+ions to the ASSA solution, an instant green fluorescence is observed at 485 nm due to the chelation of Zn2+ ions with ASSA with a stoichiometric ratio of 1:1, evident from the Job's plot and revealed binding constant as 2.6 × 105 M−1. This green fluorescence is reversed in the presence of PO 4 3− ions, proving that our modeled fluorosensor could be a reliable candidate for the cascade detection of Zn2+ and PO 4 3− ions. Along with our modeled fluorosensor, ASSA bears an outstanding selectivity and targeted sensitivity with a detection limit of Zn2+and PO 4 3− ions as 16.65 nM and 0.134 μ M , respectively, in a 10 % H 2 O-DMSO medium. A super handy paper-cuts-based experiment has been performed to recognize and quantify Zn2+ ions in the Cd2+, Hg2+, and other metals crowding situation. Also, we have constructed an INHIBIT logic gate based on the "on-off" fluorescence behavior of ASSA towards Zn2+ ions. A Sulfone-based fluorogenic probe, ASSA , has been introduced for cascade detection of Zn2+ and PO 4 3− ions displaying off-on-off green fluorescence with the detection limit of 16.65 nM and 0.134 μ M , respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

A benzoxazole-based smart molecule has been designed and developed for cascade detection of zinc and phosphate ions and its implication towards molecular logic circuit constructions has been demonstrated. [Display omitted] • A benzoxazole-based 'off-on-off' chemosensors has been employed to detect Zn2+ and PO 4 3− ions. • An INHIBIT logic circuit has been framed based on these chemical inputs and optical outputs. • A progressive logic circuit presenting "Write-Read-Erase-Read" has been constructed. • A security keypad lock has been created based on the reversibility of OPMP. • An OPMP staining paper strips-based test kit has been demonstrated. A benzoxazole-based fluorescent chemosensor (OPMP) has been designed, synthesized, and characterized by various analytical techniques. The as-prepared OPMP is employed for the cascade detection of Zn2+ and PO 4 3- ions, respectively, based on the 'off–on-off' photoluminescence mechanism in 30% (v/v) water-DMSO mixture. A significant fluorescence enhancement of OPMP at 495 nm is observed due to chelation-enhanced fluorescence upon binding with Zn2+ ions. A visual bluish-green color could be seen under 365 nm UV light irradiation, which is also well supported by the color chromaticity diagram. The fluorescence of the Zn2+chelated OPMP complex is quenched in the presence of PO 4 3- ions. The sensitivity of OPMP and Zn2+chelated OPMP complex towards detection of Zn2+ and PO 4 3- ions can be possible down to 38 nM and 48 nM, respectively. Such as dual ions detection system with outstanding reversibility and reproducibility led us to consider our OPMP as a feasible candidate for the construction of molecular logic circuits, molecular keypad locks, and set-reset memorized molecular devices. Further, an OPMP staining paper strips-based test kit has been fabricated and demonstrated for the sequential detection of Zn2+ and PO 4 3- ions, respectively. [ABSTRACT FROM AUTHOR]

The reversible acidochromic behavior of a benzoxazole-based scaffold (BPP) has been explored, and a reconfigurable dual output molecular logic gate has been constructed. [Display omitted] • Reversible acidochromism of a benzoxazole-based scaffold (BPP) has been explored. • BPP shows excellent sensitivity towards acid-base in the non-aqueous medium. • A colorimetric test strip is demonstrated to detect acid-base in the solution and gas phase. • DFT and 1H NMR analysis elucidate the mechanistic aspects of acid-base sensing. • A reconfigurable dual outputs combinatorial logic circuit INH/IMPLY has been constructed. This report explores the reversible acidochromism of a benzoxazole-based scaffold (BPP), which is highly sensitive to the acid-base in the liquid and gas phases. With the addition of acid, the solution of BPP changes its color from yellow to pink fuchsia due to the transformation of its imine into quinonoid form. Colour change is completely reversible in the presence of the base, confirming the reversible acidochromic behavior of the present BPP system. Further, a paper strips-based test kit has been demonstrated for the practical utility of the present acidochromic BPP to identify a trace amount of acid-base in solution and gas-phase, respectively. The mechanistic aspect of detection of acid-base and colorimetric change in the presence of acid-base have been explored by density functional theoretical investigations and 1H NMR experiments. Moreover, we have constructed a reconfigurable dual-output combinatorial logic circuit by utilizing the spectral shift between two wavelengths at 404 nm and 552 nm, respectively, and colorimetric change of the BPP in the presence and absence of acid-base. [ABSTRACT FROM AUTHOR]