Constructions of new luminescent 3D porous MOFs with high stability, unique selectivity and low detection limits for various ions in aqueous solution

• Published in: Journal of solid state chemistry 2020-05, Vol.285, p.121270, Article 121270
• Main Authors: Jin, Jing, Liu, Yanchen, Wang, Meng, Liu, Yizhou, Yang, Guoping, Wang, Yao-Yu
• Format: Article
• Language: English
• Subjects: Fluorescence sensing; Low detection limits; MOFs; SBUs; Water stability
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2020.121270

Three new luminescent metal-organic frameworks (MOFs), {[Zn(L)(H2O)]·2H2O}n (1), {[Pb(L)]·0.5DMA}n (2), and {[Cd2(L)2(H2O)2]·2H2O}n (3) were synthesized by an asymmetric N-containing 2-pyrimidin-5-yl-terephthalic acid (H2L) ligand with Zn2+, Pb2+, and Cd2+ ions, respectively. In these complexes, L2− ligand exhibits the multiple coordination modes with metal ions to form different new structures; especially there exist the different secondary building units (SBUs) in 2 and 3. The solid-state luminescent properties of complexes 1-3 were studied at room temperature and the mechanism was analyzed carefully. In particular, complex 2 has good stability in aqueous solution and exhibits the specific selectivity and sensitivity to probe Fe3+, MnO4−, CrO42− and Cr2O72− simultaneously, and the detection limits of Fe3+ and Cr2O72− ions are 5.6 ​× ​10−5 and 10−6, respectively. These are lower than those of other reported sensors. Finally, its quenching mechanism has also been studied in detail. Three new luminescent MOFs were synthesized successfully, where the L2− ligand exhibits the multiple coordination modes with metal ions to form new different structures; especially there exist the different secondary building units (SBUs) in 2 and 3. Complex 2 has good stability in aqueous solution and exhibits the specific selectivity and sensitivity to Fe3+, MnO4−, CrO42− and Cr2O72− ions. [Display omitted] •Three new luminescent MOFs with Zn2+, Pb2+, and Cd2+ ​ions were prepared successfully by a new N-containing ligand.•The L2- ligand may exhibit the multiple coordination modes with various metal ions to form different new structures.•The solid-state luminescent properties of ​1-3 ​were studied at room temperature and the mechanism was analyzed.•Complex ​2 ​can selectively probe Fe3+, MnO4−, CrO42− ​and Cr2O72− ​simultaneously in the aqueous solution.The detection limit can reach 10-4 ​to 10-6, which is lower for detection with those of the reported sensors.