Simple salicylaldimine-functionalized dipodal bis Schiff base chromogenic and fluorogenic chemosensors for selective and sensitive detection of Al3+ and Cr3

• Published in: Inorganica Chimica Acta 2020-01, Vol.499, p.119192, Article 119192
• Main Authors: Chandra, Rukhmani, Manna, Amit Kumar, Sahu, Meman, Rout, Kalyani, Patra, Goutam K.
• Format: Article
• Language: English
• Subjects: Al3+ and Cr3+ sensors; Cation sensing; Colorimetric sensor; Dipodal ligands; Fluorescent sensor; Salicylaldimine-functionalized bis Schiff base
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.119192

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 CH3CN-H2O (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. [Display omitted] •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 CH3CN-H2O (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.