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 (Ca2+, Mg2+, Cr3+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) could quench the fluorescence intensity of a tetrahydrofuran solution of the dye and the copolymer at different levels. The effect of Fe3+ 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 Fe3+ concentration in the range 1.33 x 10(-7)-4.00 x 10(-4) mol L-1. The polymeric sensor in a film state exhibited a dynamic response to Fe3+ in the concentration range from 3.44 x 10(-6) to 3.04 x 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 Fe3+ cations. (C) 2008 Society of Chemical Industry