A novel ratiometric probe based on rhodamine B and coumarin for selective recognition of Fe(Ⅲ) in aqueous solution

•Probe L, a new ratiometric fluorescence probe for Fe3+ was firstly synthetized based on rhodamine B and coumarin.•Probe L upon addition of Fe3+ generated two fluorescence peaks at 580 nm and 460 nm.•Probe L was a novelty design of ratiometric probe of Fe3+, due to CHEF process generated along with the PET process suppressed simultaneously.

We have developed a new ratiometric fluorescence probe based on rhodamine B and coumarin to monitor the Fe3+ with high sensitivity and selectivity. Upon addition of Fe3+ to aqueous solution of the probe, two fluorescence peaks at 580 nm and 460 nm were observed, which belong to rhodamine B and coumarin, respectively. This is a novelty design of ratiometric probe of Fe3+, due to CHEF process generated along with the PET process suppressed simultaneously. The fluorescence intensity at 580 nm was significantly increased about 120-fold with 5 equiv. of Fe3+ added in aqueous solution.