A superior luminescent metal-organic framework sensor for sensing trace Al3+ and picric acid via disparate charge transfer behaviors

A thermal stable luminescent Cu(I)-MOF [CuI(BPDPE)]n (1) based on a twisted bipyridyl ligand (BPDPE = 4,4′-bis(pyridy)diphenyl ether) was synthesized successfully and fully characterized. Complex 1 displays a 2D+2D→3D inclined penetrated structure linked by BPDPE with [CuI]2 cluster. Photoluminescent experiment exhibits 1 featuring ligand-based emission, and is suitable as a potential sensing material. It is surprising that complex 1 can high selectively detect Al3+ cation by fluorescence transfer enhancement effect, and the limit of detection (LOD) could reach to 2.1 × 10−6 M. Furthermore, Complex 1 can high selectively sense picric acid (TNP) via noumenal fluorescence quenching effect, and the quenching constant (Ksv) is up to 1.5 × 104 M−1. The mechanisms of complex 1 as a luminescent sensor were also explored, especially for sensing Al3+ cation.