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

A new zinc(II) coordination polymer (Zn-CP) constructed from 4,4-dipyridyldiphenyl ether (BPDPE) and 1,2-benzenedicarboxylic acid (1,2-bdc), namely [Zn-2(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 onedimensional chain [Zn(1,2-bdc)](n) connected by BPDPE, and finally forms a three-dimensional network through pi center dot center dot center dot pi 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 (K-sv) is 1.99 x 10(4) M for TNP with the detection limit (LOD) of 2.54 x 10(-)(6) M; the K-sv is 1.0 x 10(4) M for Fe3+, and LOD is 6.1 x 10(-)(6) M. In addition, the mechanisms of fluorescence quenching have been studied experimentally and theoretically.

Automated summary

A new zinc(II) coordination polymer Zn-CP has been discovered, showing excellent thermal and acid/base stability, high selectivity for detecting TNP and Fe3+ in aqueous solutions with high sensitivity. The fluorescence quenching mechanisms have been studied experimentally and theoretically.