Fluorometric determination of Fe3+ and polychlorinated benzenes based on Tb3+-pyromellitic acid coordination polymer

A luminescent Tb3+-pyromellitic acid (H4L = pyromellitic acid) coordination polymer (Tb-H4L CP, TbL0.5(H2L)0.5(H2O)·DMF) was prepared for multiresponsive fluorescence sensor. The Tb-H4L CP exhibits uniform nanospheres with average diameter of 220 ± 20 nm, good crystalline structure, and good dispersion in water. The Tb-H4L CP emitted the characteristic green fluorescence through antenna effect from H4L which was an excellent antenna molecule when excited at 270 nm and could be used to selectively determine Fe3+ and polychlorinated benzenes based on fluorescence quenching effect. The coordination between Fe3+ and carboxylic oxygen of Tb-H4L to damage the antenna effect and polychlorinated benzenes absorb the excitation light to result the inner-filter effect of fluorescence, which quenched the fluorescence of Tb-H4L CP. The linear range for Fe3+ was 2.0–100 μM with a detection limit of 0.7 μM and for 1,3,5-trichlorobenzene was 0–0.44 × 103 ppm with a detection limit of 0.087 ppm. The Tb-H4L CP demonstrates excellent fluorescence sensing performances, indicating that it can be used as a multi-response sensor to effectively measure toxic and harmful substances.