Two luminescent lanthanide coordination polymers incorporating free pyridyl sites as the multi-responsive sensors for hazardous ions

• Published in: Dyes and pigments 2022-07, Vol.203, p.110384, Article 110384
• Main Authors: Zhang, Lu, Liu, Xing, Zhou, Jian, Huang, Chun-Mei, Ouyang, Congrui
• Format: Article
• Language: English
• Subjects: Europium; Lanthanide coordination polymers; Luminescent properties; Sensors; Terbium
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2022.110384

The fast and effective detection of hazardous ions is very necessary owing to their serious effects on the ecological environment and human health. In this work, π-conjugated 1,10-phenanthroline (phen) chromophore has been utilized in combination with 2,2′-bipyridine-3,3′-dicarboxylate (H2bpdc) as a double-pyridyl-functionalized spacer to create two luminescent lanthanide coordination polymers [Ln2(phen)2(bpdc)3(H2O)2]n·6nH2O {Ln = Eu (1) and Tb (2)}, which were characterized by elemental analysis, thermogravimetric analyses, PXRD, single-crystal X-ray diffraction, IR and UV/Vis spectroscopy. 1 and 2 consist of free H2O molecules and 1-D polymeric chains [Ln2(phen)2(bpdc)3(H2O)2]n constructed by the linkages of [Ln(phen)(H2O)]3+ groups and bpdc2− ligands. Owing to the existence of free Lewis basic pyridyl sites as the receptor, 1 and 2 exhibit fast response (approximate 20–50 s) and high efficiency for detecting various hazardous ions (Pb2+, Fe3+, Co2+, Cu2+, Al3+, CrO42− and Cr2O72−) in aqueous solution, which have the higher Ksv values of 1.80 × 104–9.78 × 104 M−1 and the lower detection limits of 0.939–6.826 ppm. Intriguingly, most of the reported luminescent lanthanide coordination polymers can be served as either separate- or dual-responsive sensors for the detection of hazardous ions to date, however, reports on the multi-responsive sensors of a multiplicity of hazardous ions in aqueous media are relatively scarce. Therefore, 1 and 2 can be regarded as a new type of the multi-responsive sensor for fast and effectively detecting a variety of hazardous ions in water. The free pyridyl sites of 1-D europium coordination polymeric framework as the receptor can fast and effectively recognize a multiplicity of hazardous ions (Pb2+, Fe3+, Co2+, Cu2+, Al3+, CrO42− and Cr2O72−). [Display omitted] •Two luminescent lanthanide coordination polymers were prepared.•1 and 2 can act as the multi-responsive sensors for various hazardous ions.•1 shows characteristic Eu3+ emission with the higher quantum efficiency of 56.2%.