A luminescent 2D zinc(II) metal–organic framework for selective sensing of Fe(III) ions and adsorption of organic dyes

Abstract

A 2D porous multifunctional Zn(II) metal–organic framework (MOF) [ZnL(H2O)3]·3H2O·DMF (BIPT-1·3H2O·DMF) has been successfully synthesized by using bis-(3-carboxy-phenyl)furan-2,5-dicarboxamide (H2L) as organic linkers under solvothermal conditions and characterized by single crystal X-ray diffraction analysis, IR spectroscopy, thermogravimetric analyses (TGA) and powder X-ray diffraction spectra (PXRD). The participation of long chain flexible organic ligands (H2L) not only offered BIPT-1·3H2O·DMF larger pore size and stronger fluorescence emission as expect, but also introduced more functional groups and active sites into the MOF structure which is conducive to its further applications. The luminescence analysis indicated that BIPT-1·3H2O·DMF exhibited a high selectivity and sensitivity fluorescence quenching toward to Fe3+ ions in water medium, which can be observed by naked eyes under UV light. This remarkable quenching effect can be explained by the competitive absorption of excited energy mechanism and the impediment of energy transfer mechanism. Meanwhile, BIPT-1·3H2O·DMF exhibited a rare capability of neutral MOF, i.e., to selectively adsorb cationic dyes, especially for methylene blue.