Multiresponsive Adenine-Based Luminescent Zn(II) Coordination Polymer for Detection of Hg2+ and Trinitrophenol in Aqueous Media

The present work reports the synthesis, characterization, and crystal structure of a neutral two-dimensional adenine-based luminescent coordination polymer (LCP) with Zn(II) metal nodes. The photoluminescence property of the d10 LCP [Zn(μ2-1H-ade)(μ2-SO4)] (1) has been exploited to use 1 as a dual detection probe for the selective sensing of Hg2+ and 2,4,6-trinitrophenol (TNP) in the aqueous phase from among a variety of cations and a pool of aromatic nitro compounds, respectively. Competitive fluorometric experiments involving a series of cation combinations or mixture of nitro compounds established 1 as an efficient and selective sensor for Hg2+ and TNP in aqueous solutions. The limits of detection for sensing of Hg2+ and TNP in aqueous solutions using LCP 1 are 70 and 0.4 nM, respectively. For in-field sensing applications, 1-coated test paper strips have been developed. They show luminescence upon exposure to UV radiation, and the luminescence intensity is quenched upon addition to aqueous solutions of the target analytes. The present investigation clearly demonstrates selective, recyclable detection of lethal environmental pollutants such as Hg2+ and TNP in aqueous media, which has relevance in the context of environmental protection and homeland security.