Lanthanide Coordination Polymers with Tetrafluoroterephthalate as a Bridging Ligand: Thermal and Optical Properties

Abstract

By slow diffusion of triethylamine into a solution of 2,3,5,6-tetrafluoroterephthalic acid (H2tfBDC) and the respective lanthanide salt in EtOH/DMF single crystals of seven nonporous coordination polymers, (∞)(2)[Ln(tfBDC)(NO(3))(DMF)(2)]·DMF (Ln(3+) = Ce, Pr, Nd, Sm, Dy, Er, Yb; C2/c, Z = 8) have been obtained. In the crystal structures, two-dimensional square grids are found, which are composed of binuclear lanthanide nodes connected by tfBDC(2-) as a linking ligand. The coordination sphere of each lanthanide cation is completed by a nitrate anion and two DMF molecules (CN = 9). This crystal structure is unprecedented in the crystal chemistry of coordination polymers based on nonfluorinated terephthalate (BDC(2-)) as a bridging ligand; as for tfBDC(2-), a nonplanar conformation of the ligand is energetically more favorable, whereas for BDC(2-), a planar conformation is preferred. Differential thermal analysis/thermogravimetric analysis (DTA/TGA) investigations reveal that the noncoordinating DMF molecule is released first at temperatures of 100-200 °C. Subsequent endothermal weight losses correspond to the release of the coordinating DMF molecules. Between 350 and 400 °C, a strong exothermal weight loss is found, which is probably due to a decomposition of the tfBDC(2-) ligand. The residues could not be identified. The emission spectra of the (∞)(2)[Ln(tfBDC)(NO(3))(DMF)(2)]·DMF compounds reveal intense emission in the visible region of light for Pr, Sm, and Dy with colors from orange, orange-red, to warm white.

Synthesis of a Fe–Ni Alloy on a Ceria Support as a Noble‐Metal‐Free Catalyst for Hydrogen Production from Chemical Hydrogen Storage Materials

“…In a different approach focusing on the optical properties it was reported that CPs with perfluorinated ligands show a significantly enhanced luminescence 10. In this context, we observed a bright luminescence in CPs of 4f elements with tetrafluoroterephthalate (tF‐BDC 2– ) as bridging ligand 11. Obviously, the replacement of C–H by C–F entities reduces the quenching of luminescent properties by C–H vibrations significantly.…”

Lanthanide Tetrafluoroterephthalates for Luminescent Ink‐Jet Printing

“…Lanthanide complexes with the ftp 2anion were previously reported, [11][12][13] but they were synthesized under solvothermal conditions to obtain single crystals and contained coordinated solvent molecules in the coordination sphere, such as DMSO and DMF, which made them insoluble in water. To obtain watersoluble tetrafluoroterephthalates, Ln 2 ftp 3 ·xH 2 O, and to examine their water solubility and stability in water, pH titration of two aqueous solutions was performed: (1) H 2 ftp and (2) a mixture of H 2 ftp and a stoichiometric amount of Eu(NO 3 ) 3 .…”

Synthesis of Octafluorobiphenyl-4,4′-dicarboxylic acid and photoluminescent compounds based thereon

“…13.42 g (99.8 mmol) of CuCl 2 was added to a solution of the organozinc reagent II prepared from 19.98 g (83.2 mmol) of compound I, 16.32 g (249.6 mmol) of Zn powder, 1.58 g (8.32 mmol) of SnCl 2 , and 45 mL of anhydrous DMF [19]; the mixture was stirred during 6 h at room temperature. Then the reaction mixture was diluted with 300 mL of water, the product was extracted with CH 2 Cl 2 (3 × 50 mL), the organic solutions were separated and dried over MgSO 4 .…”