A thermal and pH stable fluorescent coordination polymer for sensing nitro explosives or metal ions with high selectivity and sensitivity in aqueous solution

Abstract

Abstract A new zinc(II) coordination polymer (Zn-CP) constructed from 4,4-dipyridyldiphenyl ether (BPDPE) and 1,2-benzenedicarboxylic acid (1,2-bdc), namely [Zn2(1,2-bdc)2(BPDPE)2]n (1), has been discovered using the solvothermal method. Complex 1 is a two-dimensional sheet with uncoordinated pyridine group composed of one-dimensional chain [Zn(1,2-bdc)]n connected by BPDPE, and finally forms a three-dimensional network through π···π interactions. Complex 1 shows excellent thermo and acid/base stability in aqueous solutions with a pH of 2–12. Further research indicates that complex 1 has high selectivity for the detection of TNP and Fe3+ by fluorescence sensing. The quenching constant (Ksv) is 1.99\xa0×\xa0104\xa0M for TNP with the detection limit (LOD) of 2.54\xa0×\xa010−6\xa0M; the Ksv is 1.0\xa0×\xa0104\xa0M for Fe3+, and LOD is 6.1\xa0×\xa010−6\xa0M. In addition, the mechanisms of fluorescence quenching have been studied experimentally and theoretically.