Synthesis and photophysical properties of a novel green fluorescent polymer for Fe³⁺ sensing

BACKGROUND: In recent years, environmental pollution has become a major concern for industrial societies. The design of highly selective and sensitive sensor materials has become a very important scientific goal. RESULTS: A novel 4‐amino‐substituted 1,8‐naphthalimide dye with intense green fluorescence was synthesized. The dye was then copolymerized with methyl methacrylate. The presence of metal cations (Ca 2+ , Mg 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ ) could quench the fluorescence intensity of a tetrahydrofuran solution of the dye and the copolymer at different levels. The effect of Fe 3+ was much stronger than that of the other cations. There was a good linear correlation between F 0 / F ( F 0 and F are the fluorescence intensities in the absence and presence of the metal ions, respectively) and the Fe 3+ concentration in the range 1.33 × 10 −7 –4.00 × 10 −4 mol L −1 . The polymeric sensor in a film state exhibited a dynamic response to Fe 3+ in the concentration range from 3.44 × 10 −6 to 3.04 × 10 −3 mol L −1 and the average response time was about 20 s. CONCLUSION: In view of the selectivity and rapid responsivity of the polymer sensor studied, it could be used as a new polymeric sensor for water pollution by Fe 3+ cations.