Multiresponsive water-stable luminescent Cd coordination polymer for detection of TNP and Cu2+

Abstract

A new water-stable Cd coordination polymer, namely {Cd(INA)(pytpy)(OH)·2H2O}n (1, pytpy = 4′-(4-Pyridinyl)-2,2′:6′,2”-terpyridine, INA = Isonicotinic acid) had been synthesized and structurally characterized by single crystal and powder X-ray diffractions, elemental analysis, FT-IR spectroscopy and TGA. X-ray structural analysis reveals that 1 is constructed by seven-coordinated Cd ions, INA bridges and chelated pytpy ligands, and adopts a 2D supramolecular layered structure sustained through π-π interaction. Luminescence measurements exhibit that 1 can detect 2,4,6-trinitrophenol (TNP) with high sensitivity, selectivity and recyclability in DMF or aqueous medium. The test paper experiment provides a simple and reliable detection method for TNP in practical applications. Moreover, 1 can selectively sense Cu2+ ion in aqueous solutions with a very large quenching coefficient Ksv of 1.3 × 105 M−1, which is comparable to the current maximum. The emission quenching mechanisms of the sensing properties of 1 towards TNP and Cu2+ were preliminarily studied as well. These results demonstrate that 1 can serve as an excellent sensor for TNP and Cu2+ through luminescence quenching process.