Synthesis and Characterization of Three Ytterbium Coordination Polymers Featuring Various Cationic Species and a Luminescence Study of a Terbium Analogue With Open Channels

Four novel metal-organic frameworks with 4,4′-oxybis(benzoate) (OBA) ligands and suitable cationic species, [NH3(CH2)2NH3]0.5[Yb(OBA)2(H2O)] (1), (NH4)[Yb(OBA)2(H2O)2] (2), Na[Yb(OBA)2]·0.4DMF·1.5H2O (3), and Na[Tb(OBA)2]·0.4DMF·1.5H2O (4), have been synthesized and structurally characterized. The two-dimensional structure of 1 possesses open channels filled with ethylenediamine cations. The two-dimensional structure of 2 contains the network featuring organic ligands with uncoordinated functional RCO2 groups suspended within the windows. The three-dimensional structure of 3, in which Na+ cations replaced the NH4+ cations of 2 and the presence of DMF molecules, adopts an open framework with large rhombic channels. The evacuated phase “Na[Yb(OBA)2]” in 3 retained rigidity and crystallinity to a high temperature. Framework 4, a terbium analogue of 3, has the potential sensing ability; it exhibited gradually increasing luminescence intensities when dispersed sequentially in water, methanol, and ethanol as suspensions.