A novel rhodamine phosphorus derivative as fluorescent and colorimetric sensor for highly selective detection of Fe3+ in solution

Based on Rhodamine moiety, a novel phosphorus fluorescent sensor as 2-(6-(diethylamino)-2-((diphenylphos-phoryl) methyl)-3-oxo-3-3H-xanthen-9-yl) benzoic acid (ROAP) is firstly designed and synthesized for the detection of Fe3+ in solution. The recognition effect of ROAP sensor is investigated carefully in dimethyl sulfoxide-water (DMSO-H2O) (f(w) = 70%) dispersion system. Fe3+ ion can lead to the quenching fluorescence and fading color of ROAP sensor. The as-prepared ROAP sensor shows high sensibility, selectivity, and anti-interference for Fe3+ in the concentration range of 0-5 equivalents. The recognition mechanism of the sensor is attributed to the combination of Fe3+ ions with the ROAP sensor via O atoms of P = O and OH groups. The stoichiometric ratio of ROAP and Fe3+ complexation is 2:1. The probe also exhibits good reversibility, and high potential commercial applications in the future.