Stable zinc metal-organic framework as efficient bifunctional fluorescent probe for selective detection of nitrobenzene and Fe(Ⅲ)

The coordination polymer, (Zn(II)-CP, 1), {[Zn(2,6-NDC)(4-Cltpy)](H2O)4} (1) (2,6-H2NDC = 2,6-naphthalene dicarboxylic acid and 4-Cltpy = 4'-chloro-[2,2';6',2″]terpyridine) is structurally characterized by single crystal X-ray diffraction measurement and other physicochemical studies (PXRD, FTIR, thermal analysis, microanalytical data). 4-Cltpy acts as end-capping ligand, and NDC2- is a carboxylato bridging motif to constitute ZnN3O2 distorted trigonal bipyramid core that propagates to construct 1D chain. The coordination polymer, 1, detects total iron (Fe3+ and Fe2+) in aqueous solution by visual color change, colorless to pink. Absorption spectrophotometric technique in aqueous medium measures the limit of detection (LOD) 0.11 μM (Fe2+) and 0.15 μM (Fe3+), and binding constants (Kd) are 6.7 × 104 M-1 (Fe3+) and 3.33 × 104 M-1 (Fe2+). Biocompatibility of 1 is examined in live cells, and intracellular Fe2+ and Fe3+ are detected in MDA-MB 231 cells. Zn(II) substitution is assumed upon addition of FeIII/FeII solution to the suspension of the coordination polymer, 1, in water-acetonitrile (41:1) (LZnII + FeIII/II → LFeIII + ZnII, where L is defined as coordinated ligands), which is accompanied by changing from colorless to pink at room temperature. The color of the mixture may be assumed to the charge transfer transition from carboxylate-O to Cltpy via Fe(II/III) bridging center (carboxylate-O-Fe-CltPy). The product isolated from the reaction is finally characterized as Fe(III)@1-CP. It is presumed that product Fe(II)@1-CP may undergo fast aerial oxidation to transform Fe(III)@1-CP. The FeIII exchanged framework (Fe(III)@1-CP) has been characterized by PXRD, IR, TGA and energy dispersive X-ray analysis (EDX)-SEM. The MTT assay calculates the cell viability (%), and the tolerance limit is 100 μM to total Fe2+ and Fe3+.

Spectrophotometric Determination of Trace Amount of Total FeII/FeIII and Live Cell Imaging of a Carboxylato Zn(II) Coordination Polymer.

A stable Cd metal–organic framework as efficient fluorescent probe for sensing Fe3+ in water

Abstract A new coordination polymer, [Co(SDA)(TBZH)(H2O)]n (1, SDA = trans-4,4'-stilbenedicarboxylic acid tetra-anion, TBZH = thiabendazole) has been synthesized under hydrothermal condition. The structure has been determined by X-ray diffraction, thermal gravimetric analysis (TG), infrared spectrum (IR) and Magnetic properties. The structure of 1 contains one Co(II), the metal center Co(II) is five-coordinated and through the SDA, it bridged an infinite one-dimension chain. In TG curve, there are three weight loss steps and the residual may be CoO. The static and dynamic magnetic properties of the high-spin Co(II) polymer 1 were measured, there is no SCM properties exhibited by the polymer.

Meng-Yue Xu

Papers

A stable Cd metal–organic framework as efficient fluorescent probe for sensing Fe3+ in water

Crystal structure, IR, TG, and magnetic properties of a thiabendazole aqua-cobalt(II) 4,4'-stilbenedicarboxylate