A water-stable Zn(II) coordination polymer for a high sensitivity detection of Fe3+ and 2,4,6-trinitrophenol

A Zn(II) coordination polymer [Zn(L) (H2O)2]n (1, 1-Zn) (H2L ​= ​5-(pyrazin-2-yl)isophthalic acid) was synthesized through hydrothermal synthesis and systematically characterized. 1 is a three-dimensional (3D) framework with an uninodal 3-connected bto topology. Interesting, two helical chains and a zigzag chain are grouped together to form a 3D framework of 1. Moreover, 1 shows good chemical stability towards common organic solvents and high hydrothermal stability. The suspension of 1 shows good luminescence performance in water. Further luminescence experiments display that 1 shows high sensitivity and selectivity for sensing Fe3+ ion and TNP (2,4,6-trinitrophenol) in aqueous media. The highest quenching constants (Ksv) and the lower the limits of detection (LODs) are about 1.7 ​× ​104 ​M−1 and 0.44 ​μM for Fe3+, and 3.8 ​× ​104 ​M−1 and 0.19 ​μM for TNP, respectively. In addition, the possible luminescence sensing mechanisms were carefully investigated by PXRD, IR, XPS (X-ray photoelectron spectroscopy), and UV spectroscopy. The results demonstrate that 1 can be used as a bifunctional luminescent probe for sensing Fe3+ ion and TNP (2,4,6-trinitrophenol) in aqueous media.