Two water-stable Zn(II) complexes for highly sensitive sensing of Cr2O72− ions and levofloxacin

Abstract

Two new Zn(II) complexes, formulated as [Zn(L1)0.5(DCTP)·(H2O)] (1) and [Zn(L2)(DCTP)] (2) (L1 = 1,4-bis(1-(pyridin-4-ylmethyl)-1H-benzo[d]imidazol-2-yl)butane, L2 = 1,2-bis(1H-benzo[d]imidazol-2-yl)cyclohexane, H2DCTP = 2,5-dichloroterephthalic acid), were hydrothermally synthesized and characterized. 1 and 2 display the 2D and 0D structures, respectively, which can generate 3D and 2D supramolecular networks via hydrogen bond interactions. Two Zn(II)-based complexes show high stability in water and different pH solutions. Notably, 1 and 2 exhibit effective sensing characteristics toward Cr2O72− ions and levofloxacin, including high sensitivity and selectivity, fast response and good recoverability. The fluorescent sensing mechanisms of two complexes were further investigated from the perspective of energy transfer and photoinduced electron transfer.