A gas-selective Zn-MOF exhibits selective sensing of Fe3+ ions by doping with Tb3+

Abstract

Here, a new Zn²⁺ metal organic framework, {[Me₂NH₂][Zn₂(L)(DTZ)]·2DMF·3H₂O}_n (Zn-MOF), has been synthesized with low-symmetric carboxylic acid ligand 2,6 bis(2′,5′-dicarboxyphenyl)pyridine (H₄L) as the main ligand and 3,5-diamino-1,2,4-riazole (DTZ) containing an electron-rich N atom as an auxiliary ligand. Because of its high structural stability and adsorption properties, it can be used to efficiently separate CO₂/CH₄ and C₂H₂/CH₄. In addition, Tb@Zn-MOF was obtained by doping with Tb³⁺ to partially replace Zn²⁺. A study of its luminescence sensing performance demonstrated that Tb@Zn-MOF showed intense luminescence properties and can be used for the directional detection of Fe³⁺ in aqueous solution. Furthermore, PXRD analysis, UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS) were also used to study possible luminescence sensing mechanisms. The recognition mechanism for Fe³⁺ ions is believed to be caused by electron transfer.