A new Tb(iii)-functionalized layer-like Cd MOF as luminescent probe for high-selectively sensing of Cr3+

Abstract

A new layer-like metal–organic framework {[Cd₄(NDIC)₄·5DMF·H₂O]DMF}_n (NDIC = 5-(5-norbonene-2,3-dicarboximide) isophthalic acid) was synthesized by solvothermal method. It was used as a parent framework to encapsulate Tb³⁺ cations in Cd-MOF. The obtained composite Tb(3+)@Cd-MOF exhibited excellent luminescence and produced a remarkable quenching effect in the luminescence emission of Tb³⁺ upon the introduction of Cr³⁺. Subsequently, Tb(3+)@Cd-MOF was developed as a highly selective and sensitive probe for detection of Cr³⁺. In particular, the luminescence probe of Cr³⁺ had a low detection limit (7.5 × 10⁻⁸ M), a broad linear range (1 × 10⁻⁷–5 × 10⁻⁶ M). A paper strip coated with Tb(3+)@Cd-MOF was also shown to be highly selective to Cr³⁺ under the irradiation of 254 nm UV light of by the naked eyes. This is the first example for detecting metal ions based on a lanthanide functionalized new metal–organic framework (MOF).