A water-stable luminescent Co(II) coordination polymer as probe for efficient detection of Cr(VI)-anions (Cr2O72- and CrO42-) in aqueous solution

A new 2D Co(II)-based coordination polymer (CP), {(Co(TCPA)(L)]center dot H2O}(n). (1) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yflpropane, and H(2)TCPA = 2,3,5,6-tetrachloroterephthalic acid), was successfully constructed under hydrothermal condition. 1 features a 2D (4,4)-connected layered structure. Adjacent sheets of 1 are interconnected via pi center dot center dot center dot pi stacking interactions generating a 3D supramolecular framework. Further, 1 exhibits the high sensing ability for Cr2O72- (pH = 4.0) and CrO42- (pH = 11.0) in aqueous systems through luminescence quenching effects. The K-sv values are 1.43 x 10(4) M-1, and 1.24 x 10(4) M-1 for Cr2O72-, and CrO42-, respectively. Besides, the possible selective fluorescence sensing mechanism was speculated.