A three-dimensional Cd(ii) metal–organic framework: a bifunctional luminescence sensor for benzaldehyde and Fe2+ ions

Abstract

A solvothermal reaction between Cd(NO₃)₂·4H₂O and the bifunctional ligand 3,5-bis-(1H-1,2,4-triazol-1-yl)benzene carboxylic acid (HTBC) afforded a three-dimensional coordination polymer, namely [Cd_0.5(TBC)]_n (1). Single-crystal X-ray diffraction analyses exhibited that MOF 1 possesses a 3D framework with rtl topology, which exists in the form of 2-fold interpenetrated networks. Its luminescence properties demonstrated that complex 1 is a very suitable MOF for the luminescence probing of Fe²⁺ cations over other metal cations with a high quenching-efficiency constant K_SV value of 1.35 × 10⁵ M⁻¹ and a low fluorescence detection limit. In addition, complex 1 also exhibits the highly selective and visually sensitive sensing of the organic contaminant PhCHO with good reusability and a low detection limit. What's more, this is a regenerable luminescent sensor for the highly selective, sensitive sensing of Fe²⁺ over Fe³⁺.