A new perylenediimide with NH functionality as a colorimetric and fluorescent probe for the selective detection of trivalent Fe3+ and Al3+ ions

Abstract

Abstract We report the synthesis of a new colorimetric probe R1, in which the perylene tetracarboxylicdiimide fluorophore is connected with an adamantly amine unit through the NH binding site. R1 was tested with a variety of metal ions and exhibited a significant colorimetric transition in the presence of Fe3+ and Al3+ ions. No significant changes were observed with other metal ions. Absorption measurements indicated that trivalent metal ions Fe3+/Al3+ bind with R1 and generate a stable complex. The presence of Fe3+ and Al3+ ions induces new absorption bands with shoulder peaks at 525 nm and 568 nm. The fluorescence intensity of R1 at 579 nm was significantly increased by the addition of Fe3+or Al3+ ions. Furthermore, R1 was found to be sensitive towards these metal ions at micromolar concentrations. The stoichiometry of R1:Fe3+/Al3+ complexes were confirmed by ESI–MS analysis, and binding constants were calculated using Benesi–Hildebrand plots. The binding mode of R1 with metal ions was proposed based on optimized structure from DFT calculation.