Two Stable Terbium-Organic Frameworks Based on Predesigned Functionalized Ligands: Selective Sensing of Fe Ions and CH/CH Separation.

To construct desired metal-organic framework (MOF) sensors, the predesigned functionalized ligands 2,5-bis(2',5'-dicarboxylphenyl)pyridine () and 2,5-bis(2',5'-dicarboxylphenyl)difluorobenzene () with pyridine- and fluorine-decorated tetracarboxylic acids were used, and two stable terbium-organic frameworks, HO[(Tb()(HO)]·2HO () and [Tb()(HCOO)(HO)]·6HO (), have been synthesized. The structures of and contain 1D open channels, which are functionalized by pyridine N or F atoms, respectively. Both of them show intense fluorescence in water and exhibit excellent selectivity and sensitivity to Fe ions. The effects of different functional group sites on the stability and fluorescence sensing performance of MOFs have also been studied. In addition, a gas adsorption study demonstrates that is capable of adsorbing CH over CH selectively.