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Abstract: Two novel isostructure open frameworks of Ln(III), [Ln(L)(H2O)·1.5H2O] n , [Ln=Pr(1), Eu(2)], have been successfully synthesized using multifunctional organic compound 7,8,4′-tricarboxymethoxyisoflavone (L) as a linker through hydrothermal technique. Compounds 1 and 2 consist of 2D networks, which are further assembled into 3D architecture with 1D channels constructed by coordination bonds and the lattice water molecules array in lines occupying these voids via hydrogen bonds. In these compounds, L only exhibit one coordination mode coordinating to Ln(III), and four oxygen atoms from two carboxylate groups and two carboxymethoxy groups of one L coordinate to one Ln(III), simultaneously. The thermogravimetric analyses of these compounds show that the coordinated water and lattice water are lost in two steps, and the final residues are lanthanide oxides. [Copyright &y& Elsevier]

A new lanthanide metal organic framework, namely [Eu(C 7 H 7 O 4 N 2)(H 2 O) 2 (Cl 0.38) 2 Cl 1.24 (1), was solvothermally synthesized using 1,3-bis(carboxymethyl)imidazolium chloride ([H 2 imdc]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(C 7 H 7 O 4 N 2)(H 2 O) 2 (Cl 0.38) 2 Cl 1.24 1 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 Eu 2 O 3 at about 589 °C. Image 1 • 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. [ABSTRACT FROM AUTHOR]

• The article we are going to contribute has the following highlights: • Two rare earth metal organic frameworks were synthesized by solvothermal method using zwitterionic 1,3-Bis(1-carboxylatoethyl)imidazolium bromide as ligand. • Complex 2 of Gd(C 9 H 11 N 2 O 4)(C 2 O 4)(H 2 O) (C 9 H 11 N 2 O 4 2‒ = 1,3-Bis(1-carboxylatoethyl) imidazolium ion, C 2 O 4 2- = oxalate) shows antiferromagnetic interactions in the temperature range 2−300 K. Good water-solubility, integrity and stability of 2 significantly different from common complexes grant it great potential in bio-related applications. Two rare earth coordination polymers named {[La 6 (C 9 H 11 N 2 O 4) 11 (H 2 O) 2 (OH) 2 ]⋅Br 5 } n (1) and [Gd(C 9 H 11 N 2 O 4)(C 2 O 4)(H 2 O)] n (2) (C 9 H 11 N 2 O 4 2‒ = 1,3-bis(1-carboxylatoethyl) imidazolium ion, C 2 O 4 2- = oxalate) were solvothermally synthesized using zwitterionic 1,3-bis(1-carboxylatoethyl)imidazolium bromide as ligand. 1 and 2 were both structurally characterized by single crystal X-ray diffraction, and their thermodynamic properties and magnetic properties of 2 were studied. In the 3D structure of 1 , La3+ ions are all ten-coordinated and exhibit three different coordination environments. This 3D structure of 1 is formed by La−O coordination bonds with Br− located in the cavities through H-bond and electrostatic attraction. Different from 1 , all Gd3+ ions in 2 have the same eight-coordinated environment. These two coordination polymers both have good thermostability until 323 °C for 1 and 375 °C for 2 , and then decompose giving rise to La 2 O 3 and Gd 2 O 3 , respectively. The magnetic behaviors of 2 are measured in the temperature range 2–300 K. [Display omitted] [ABSTRACT FROM AUTHOR]