Solvent-free synthesis of nitrone-containing template as a chemosensor for selective detection of Cu(II) in water

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 267; no. Pt 2; p. 120473
• Main Authors: Carneiro, Leonardo M., Bartoloni, Fernando H., Angolini, Célio F.F., Keppler, Artur F.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.02.2022
• Subjects: Aryl-aryl nitrones; Cu2+ detection; Limit of Detection; Modulative template; Nitrogen Oxides; Small-molecular-mass chemosensor; Solvent-free synthesis; Solvents; Water; Small-molecular-mass chemosensor; Aryl-aryl nitrones; Solvent-free synthesis; Modulative template; Cu2+ detection; Cu(2+) detection
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2021.120473

[Display omitted] •Nitrone-based compounds were used to detect metal cations in aqueous solutions.•The chemosensor candidates were isolated in 60 min, in good yields (up to 85%).•α-(Z)-Imidazol-4-ylmethylen-N-phenyl nitrone (Nit1) detected Cu(II) selectively.•Cu(II) was detected (detection limit of 0.06 ppm) over eight interferent metal cations.•Nit1 has a modulative template, is small (188 g/mol), & offers new chemosensor design. A state-of-the-art method was developed for repurposing nitrone-containing compounds in the chemosensory field, the ability of the designed molecules to chelate metal cations was evaluated, and their unprecedented solubility in water was confirmed. A facile, rapid, and solvent-free method of synthesizing small molecular mass chemosensors was developed by using a modulative α-aryl-N-aryl nitrone template. α-(Z)-Imidazol-4-ylmethylen-N-phenyl nitrone (Nit1) and α-(Z)-2-pyridyl-N-phenyl nitrone (Nit2) were prepared in 15 min, isolated in less than 60 min with ca. 90% yield, and screened against nine metal cations. Nit1 is a small-molecular-mass compound (188 g mol−1) that is water-soluble and has specificity for sensing Cu2+ with an association constant of K = 1.53 × 1010 and a limit of detection (LOD) of 0.06 ppm. These properties make Nit1 a competitive chemosensor for the detection of Cu2+ in aqueous solution. The nitrone-containing template used in this study is a step forward for new and small chemosensory entities.