A highly selective and sensitive bifunctional luminescent sensor for TNP and Iron ion based on magnesium coordination polymer

Abstract

A luminescent coordination polymer [Mg3L2(H2O)6]2·12H2O (1) (H4L+Cl-= 1,3-bis(3,5-dicarboxyphenyl)imidazolium) was synthesized and systematically characterized. Complex 1 is a 0D unit constructed by L3-, water and magnesium ions, which was further assembled into 0D → 2D → 3D network constructed via various H-bondings from free/coordinated water and π···π interactions. The fluorescence intensity of complex 1 has good stabilities in acid/base conditions, photoluminescence experiments show that complex 1 has high selectivity and sensitivity for sensing nitro compounds (NCs) and metal ions by luminescence quenching effect, especially for picric acid (TNP) and Fe3+ ions, the Ksv are up to 2.6 × 104 M−1 and 5.0 × 104 M−1. Further more, their possible quenching mechanisms have been studied separately.