flexible Tb(III) functionalized cadmium metal organic framework as fluorescent probe for highly selectively sensing ions and organic small molecules

A luminescent terbium functionalized cadmium metal-organic framework Tb3+-VCd-MOF (CdMOF = {[(Me2NH2)(2)]center dot[Cd-3(5-tbip)(4)]center dot 2DMF}(n), (5-tbipH(2) = 5-tert-butylisophthalic acid)) has been prepared via postsynthetic cation exchange. Subsequently, Tb3+@Cd-MOF is chosen as probe for sensing metal cations, anions and small organic molecules because of its high luminescent intensity and robust framework. The detailed study reveals that Tb3+@Cd-MOF has the potential to be highly selectively and sensitive probe for detection of Fe3+ (detection limit, 0.010 mM), Cr2O72- (detection limit, 0.012 mM) and acetone through its fluorescence quenching. However, the crystal structures of Tb3+@Cd-MOF with different solutions or organic solvents are in good stability, except for pyridine solvent. As a flexible MOF, a single-crystal-to-single-crystal (SCSC) transformation appears when the complex is immersed into pyridine. Furthermore, the study on fluorescence shows selective pyridine recognition through luminescent quenching. Nevertheless, the structure and luminescent intensity can be restored when we remove pyridine solvent and introduce DMF solvent into the complex. (C) 2016 Elsevier B.V. All rights reserved.