A facile coordination-assisted method to fabricate a FRET-based fluorescent probe for ratiometric analysis with improved selectivity

•Coordination-assisted method was proposed for facile linking of energy donor and acceptor.•FRET-based probe improves the detection selectivity and further discriminate Fe3+ from Al3+ with different ratiometric fluorescence responses.•The probe showed good sensitivity with 166-fold fluorescence variation in the ratios I583/I502 before and after addition of Fe3+.

Here we report a facile coordination-assisted method to construct a FRET-based probe that shows ratiometric detection of metal ions with improved selectivity. Probe 2 exhibits good sensitivity and selectivity towards the Fe3+ and Al3+ over other cations in aqueous acetonitrile solution. Probe 1 can be formed in situ by a convenient addition of Salen-Zn complex, which can further discriminate the Fe3+ from Al3+ with different ratiometric fluorescence responses.