Solvothermal syntheses and properties of europium metal organic framework with 1, 3-bis(carboxymethyl)imidazolium chloride ionic liquid

• Published in: Journal of molecular structure Vol. 1200; p. 127081
• Main Authors: Wang, Yibo, Fu, Xiaofang, Zhang, Ting, Xin, Tingting, Lu, Chichong, Yan, Dongpeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2020
• Subjects: Europium complex; Ionic liquid; Luminescence; Metal organic frameworks; Solvothermal; Metal organic frameworks; Europium complex; Solvothermal; Luminescence; Ionic liquid
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2019.127081

A new lanthanide metal organic framework, namely [Eu(C7H7O4N2)(H2O)2(Cl0.38)2]Cl1.24 (1), was solvothermally synthesized using 1,3-bis(carboxymethyl)imidazolium chloride ([H2imdc]Cl) ionic liquid as a ligand. This compound was structurally characterized by single crystal X-ray diffraction and its properties were analyzed spectroscopy and theoretical studies. In 1, Eu (III) ions have only one coordination environment, and the ligands exhibit one coordination mode. The Eu3+ ions and ligands are connected to construct wavelike 2D cationic layers through coordination bonds, and then the 2D networks further interconnected through hydrogen bonds. The luminescent properties were studied at 77 K. The emission spectrum shows that there is one Eu3+ ion site in asymmetric unit, which is consistent with the results of the X-ray crystal structure analysis. Compound 1 exhibits characteristic emission bands of Eu3+ with emission lifetime of 0.336 ms. Single crystal of metal organic framework: [Eu(C7H7O4N2)(H2O)2(Cl0.38)2]Cl1.241 was solvothermally synthesized by 1,3-bis(carboxymethyl)imidazolium ionic liquid. The single crystal data indicate Eu3+ ions have only one nine-coordinate chemical environment, which is accordance with the results of the luminescence analysis of 1. FT-IR, PXRD, thermogravimetric analysis are also in accordance with the result of single crystal structure data. The time-resolved spectra further display that there is only one Eu3+ ion site in 1 and it has the lifelime of 0.336 ms. The thermal analysis results show the organic framework of 1 can sustain until 299 °C and completely decomposed into Eu2O3 at about 589 °C. [Display omitted] •Rare earth metal organic framework crystal was synthesized by solvothermal method using ionic liquids as ligand.•The synthesized Eu-MOF is 2D cationic layers, which are further interconnected through hydrogen bonds.•It has good optical properties and the fluorescence lifetime can reach 0.336 ms.