Two colorimetric fluorescent turn-on chemosensors for detection of Al and N : Synthesis, photophysical and computational studies.

Two new rhodamine derivative L and L 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 (Al ) and azide (N ) in aqueous acetonitrile solution. Aluminum ion (Al ) triggers the formation of highly fluorescent ring-open spirolactam. The fluorescence and colorimetric response of the L -Al and L -Al complexes were quenched by the addition of N , which extracting the Al 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, H-NMR spectroscopy and density functional theory (DFT) calculations.