A bifunctional chemosensor for detection of volatile ketone or hexavalent chromate anions in aqueous solution based on a Cd(II) metal–organic framework

Abstract

Abstract A new porous metal–organic framework with chemical formula of [Cd3(cpota)2(phen)3]n·5nH2O (MOF-1) (H3cpota = 2-(4-carboxyphenoxy)terephthalic acid & phen = 1,10-phenanthroline) has been synthesized and characterized by infrared spectroscopy, elemental analysis, thermogravimetry and X-ray single crystal and powder diffracting methods. MOF-1, as a potential material of the sensing applications, has an uncommon 3D microporous structure in which the trinuclear [Cd3(phen)3(μ2-COO)4]2+ SBUs are interconnected by the V-shaped cpota3− ligands. MOF-1 has good stabilities not only in aqueous solution in the range of pH = 1.0 ∼ 14.0 but also in solid from room temperature (RT) to 330 °C. Fluorescence titration, cyclic and anti-interference experiments demonstrate that MOF-1 is an excellent probe for volatile organic ketones (acetone/2-butanone) and hexavalent chromate (CrO42−/Cr2O72−) in aqueous solution. The luminescence investigations in the aqueous solution of pH = 9 reveal that the MOF-1 can efficiently and selectively detect Cr(VI) ions without the interference of other metal cations. Quenching mechanisms are also studied in detail.