Search

A dihydrazone based novel bis Schiff base receptor, (L) has been developed for colorimetric detection of Cu2+ ion. The chemosensor L displayed excellent selectivity and sensitivity towards Cu2+ ion with detection limit value 5.3 × 10−7 M with binding stoichiometry 1:1 and association constant value 1.3 × 104 M−1. This can be applied for the detection of Cu2+ ion in real samples. [Display omitted] • A novel dihydrazone based conjugated bis Schiff base chromogenic chemosensor (L) has been developed. • L can selective detect Cu2+ ion with lower limit of detection, 5.3 × 10−7 M. • The interaction of L with Cu2+ has been confirmed with NMR, FTIR, and ESI-MS. • L can be used to detect Cu2+ ion in real samples and as test kit. A simple dihydrazone based bis Schiff base receptor L has been presented for the first time for colorimetric selective detection of Cu2+ ion in methanol-H 2 O (1:1 v/v, pH = 7.4 in HEPES buffer) with detection limit value 5.3 × 10−7 M. The binding stoichiometry was obtained as 1:1 from job's plot analysis, 1H NMR and ESI-MS spectra with the association constant value 1.3 × 104 M−1. The chemosensor L can be applied for the recovery of contaminated water samples and also successfully used to detect Cu2+ ion using a test kit coated with L. [ABSTRACT FROM AUTHOR]

A pyridine appended thiosemicarbazone based colorimetric and fluorometric turn-on probe L has been synthesized and characterized by X-ray single crystal analysis, 1H NMR, ESI-MS, UV–vis spectra and elemental analysis. The probe L , functioned as dual ions sensor to detect Cu2+ and Ag+ colorimetrically and Ag+ fluorometrically. The colorometric detection limits reached upto 1.7 and 2.2 μM for Cu2+ and Ag+ and fluorometric detection limit 1.6 μM for Ag+ ions. L has been successfully applied for the determination of Cu2+, and Ag+ ions in real water samples. • A pyridine appended thio-semicarbazide based chromogenic and fluorogenic chemosensor L has been developed. • L can recognize Cu2+ and Ag+ ions colorimetrically and Ag+ ion fluorometrically. • The detection limit reaches up to 1.7 and 1.6 μM for Cu2+ and Ag+ ions. • L can be successfully applied for the determination of Cu2+ and Ag+ ions in real water samples. A colorimetric and fluorometric turn-on probe L , (E)-1-((pyridin-4-yl)methylene) thiosemicarbazide has been synthesized and characterized by X-ray single crystal analysis, 1H- NMR, ESI-MS, UV–vis spectra and elemental analysis. The probe L , functioned as dual ions sensor to detect important metal ions Cu2+ and Ag+ in 1:1 methanol–water (v/v) solution in the presence of other cations (Fe3+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, Pb2+, Cr3+, Al3+ and Fe2+ ions) based on binding site-signalling approach, where both the thiourea moiety and pyridine N atom acts as binding sites for Ag+ ions and only pyridine N atom acts as binding site in case for Cu2+. The binding stoichiometries of probe L , with the metal ions Cu2+ and Ag+ have been confirmed by Job's plot, ESI-mass spectral analysis and DFT studies. The colorometric detection limits reached upto 1.7 and 2.2 μM for Cu2+ and Ag+ and fluorometric detection limit upto 1.6 μM for Ag+ ions. The probe L has been successfully applied for the determination of Cu2+ and Ag+ ions in real water samples. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel guanidine base colorimetric and fluorescent and bis Schiff base chemosensor L has been presented which could detect Hg2+ by "naked eye" colour changes from yellow to red and Zn2+ through selective fluorescence enhancement in CH 3 OH- tris buffer (1/1, v/v).The limit of detection for Hg2+ and Zn2+ are found to be 9.89 × 10−7 M and 1.23 × 10−6 M respectively. Moreover the chemosensor L has applications in real sample analysis in environmental and biological samples and building molecular logical devices. To the best of our knowledge, this observation is the first case where a guanidine base bis Schiff base is being utilized for sensing of metal ions. Highlights • A novel guanidine base colorimetric and fluorescent chemosensor L has been developed. • L can detect Hg2+ by "naked eye" colour change and Zn2+ through selective fluorescence enhancement. • The limit of detection for Hg2+ and Zn2+ are found to be 9.89 × 10−7 M and 1.23 × 10−6 M respectively. • The chemosensor L has applications in real sample analysis and building molecular logical devices. Abstract A novel guanidine base colorimetric and fluorescent bis Schiff base chemosensor L has been designed synthesized and characterized by elemental analyses, 1H NMR, FT-IR and ESI-MS spectral analysis. The chemosensor L could detect Hg2+ by "naked eye" colour change from yellow to red and Zn2+ through selective fluorescence enhancement in CH 3 OH- tris buffer (1/1, v/v) over other metal ions commonly obtained in physiological and environmental samples. The Job's plot analysis revealed that 1:2 and 1:1 coordination patterns for L -Hg2+ and L -Zn2+ complexes respectively, which have further been confirmed by ESI-MS spectra. The DFT calculations are also in agreement with the experimental results. The limit of detection for Hg2+ and Zn2+ are found to be 9.89 × 10−7 M and 1.23 × 10−6 M respectively, which are far below than the guidelines provided by World Health Organization (WHO) for drinking water. Moreover the chemosensor L has applications in real sample analysis in environmental and biological samples and building molecular logical devices. To the best of our knowledge, this observation is the first case where a guanidine base bis Schiff base is being utilized for sensing of metal ions. [ABSTRACT FROM AUTHOR]

Two salicylaldimine-functionalized ether based dipodal bis Schiff base low cost fluorescent colorimetric chemosensors L1 and L2 have been designed and synthesized. These sensor could simultaneously detect Al3+ and Cr3+ by change in both absorption and fluorescence intensity in CH 3 CN-H 2 O (1/1, v/v). The detections limits of the sensor L1 , for Al3+ (1.73 × 10−7 M) and Cr3+ (1.12 × 10−7 M) and of the sensor L2 , for Al3+ (4.34 × 10−7 M) and Cr3+ (7.73 × 10−7 M) are far below than the limit set by the World Health Organization (WHO) for drinking water. These chemosensors find application in colorimetric test kits and real sample analysis. • Two salicylaldimine-functionalized have been developed for detection of Al3+ and Cr3+. • They have fairly low detection limits and high association constants. • The binding stoichiometries have been confirmed as 2:2. • These chemosensors find application in colorimetric test kits and real sample analysis. Two salicylaldimine-functionalized dipodal bis Schiff base low cost fluorescent colorimetric chemosensors L1 (bis([4-(2-hydroxy-3-methoxybenzyl-ideneamino)phenyl]ether) and L2 (di[(4-phenylimino)4-diethylsalicyl-aldehyde]ether) have been designed and synthesized. These sensors could simultaneously detect two biologically important metal ions (Al3+ and Cr3+) by change in both absorption and fluorescence intensity in CH 3 CN-H 2 O (1/1, v/v) solvent mixture at physiological pH. The jobs plot analyses indicate the 2:2 binding stereochemistry for Al3+ and Cr3+ ions with both the probes L1 and L2 , which were further been confirmed by 1H NMR and ESI-MS studies. The binding constant values for L1 were found to be 2.35 × 105 M−1 for Al3+ and 1.26 × 105 M−1 for Cr3+ and in case of L2 these values are 1.46 × 105 M−1 for Al3+ and 3.0 × 105 M−1 for Cr3+. The detections limits of the sensor L1 , for Al3+ (1.73 × 10−7 M) and Cr3+ (1.12 × 10−7 M) and of the sensor L2 , for Al3+ (4.34 × 10−7 M) and Cr3+ (7.73 × 10−7 M) are far below than the limit set by the World Health Organization (WHO) for drinking water. Moreover, visible colorimetric test kits and real samples for rapid detection of Al3+ and Cr3+ could be successively applied for all practical purposes, indicating their potential use in environmental samples. [ABSTRACT FROM AUTHOR]