Gas adsorption and fluorescence studies of Cd2+ and Zn2+ metal organic frameworks based on the same fluorinated ligand

Abstract

Two new metal organic frameworks (MOFs) were synthesized by solvent-thermal synthesis with fluorinated 4,4′-(pyridine-3, 5-diyl) bis (3-fluorobenzoic acid) ligands (L1), namely {[Cd(L1)H2O]·DMF}n (MOF 1) and {[Zn(L1)]·3H2O}n (MOF 2). Single crystal X-ray diffraction analysis shows that MOF 1 is a two-dimensional structure with binuclear unit of [Cd2(COO)4N2O2]. MOF 2 displays a three-dimensional structure based on binuclear unit of Zn2(COO)2. The PXRD determination demonstrates the purity of the synthesized MOF 1 and MOF 2 samples, while the TGA shows the thermal stability of the structures. The gas adsorption studies show that MOF 1 and MOF 2 exhibit good gas adsorption characteristics, and MOF 2 has high selectivity for C2H2/CH4. Moreover, both MOF 1 and MOF 2 can selectively and sensitively detect Fe3+ in water.