Two new coordination polymers containing long flexible bis(benzimidazole) ligand as luminescent chemosensors for acetylacetone and Hg(II) ions detection

• Published in: Journal of solid state chemistry 2020-02, Vol.282, p.121132, Article 121132
• Main Authors: Zhu, Hui, Han, Chao, Li, Yue-Hua, Cui, Guang-Hua
• Format: Article
• Language: English
• Subjects: Acetylacetone; Bis(benzimidazole); Crystal structure; Hg2+ ions; Luminescent quenching
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2019.121132

Two new coordination polymers (CPs), [Cd(L)(NTA)]n (1) and [Ni(L)(NPTA)·H2O]n (2) (L ​= ​1,6-bis(benzimidazol-1-yl)hexane, H2NTA ​= ​2-nitroterephthalic acid and H2NPTA ​= ​3-nitrophthalic acid) were prepared under solvothermal conditions. Both CPs exhibit 2D layered structures with sql and hcb network, respectively. 1 and 2 are further extend into 3D supramolecular networks by π–π stacking interactions. The luminescent experiments show that 1 and 2 can serve as efficient probes for sensing acetylacetone (acac) with high quenching efficiency (Ksv ​= ​1258 ​M–1 for 1, 4841 ​M–1 for 2) and low detection limit (3.63 ​μM for 1 and 0.79 ​μM for 2). 1 and 2 also possess selective and sensitive sensing for Hg2+ with quenching efficiency 3565 ​M–1 for 1 and 7432 ​M–1 for 2 and low detection limit 3.05 ​μM for 1, 2.29 ​μM for 2, respectively. When acac and Hg2+ ions are at a low concentration, there are good linear relationships between concentrations and quenching efficiencies. 1 and 2 represent the first example based on CPs as luminescent chemosensors for acac and Hg2+ ions detection. [Display omitted] •Two new coordination polymers based on flexible bis(benzimidazole) ligand were synthesized and characterized.•1 and 2 exhibited highly sensitive and selective sensing for acac and Hg2+.•The luminescence quenching mechanism of Hg2+ were discussed.