Two colorimetric fluorescent turn-on chemosensors for detection of Al3+and N3−: Synthesis photophysical and computational studies

摘要

Two new rhodamine derivative L1 and L2 bearing 2-methoxy-1-naphthaldehyde and 5-bromo-3-methoxy salicylaldehyde units were designed and synthesized using microwave-assisted organic synthesis and utilized towards sequential fluorescence detection of aluminum ion (Al³⁺) and azide (N3⁻) in aqueous acetonitrile solution. Aluminum ion (Al³⁺) triggers the formation of highly fluorescent ring-open spirolactam. The fluorescence and colorimetric response of the L1-Al³⁺ and L2-Al³⁺ complexes were quenched by the addition of N3⁻, which extracting the Al³⁺ from the complexes and turn-off the sensors, confirming that the recognition process is reversible. The recognition ability of the sensors was investigated by fluorescence titration, Job’s plot, ¹H-NMR spectroscopy and density functional theory (DFT) calculations.