resumo
A series of fluorinated lanthanide-organic frameworks (LnOFs), formulated as [Ln(H(3)tftp)(H2O)] [where Ln(3+) = La3+ (1), (La0.95Eu0.05)(3+) (2), (La0.95Tb0.05)(3+) (3) and (La0.94Eu0.03Tb0.03)(3+) (4)], has been successfully prepared, under hydrothermal conditions, using the novel ((2,4,6-trifluorobenzene-1,3,5-triyl)tris (methylene)) triphosphonic acid (H(6)tftp) organic ligand and Ln(3+) cations as metallic centers. The three-step preparation of the tripodal H(6)tftp ligand is described. H(6)tftp and all intermediate molecules involved in the synthesis were fully characterized in the liquid and solid states. While the La3+-based LnOF material was isolated as single-crystals, with its crystal structure being fully described by single-crystal X-ray diffraction, phase identification of the Eu3+-and Tb3+-based materials was performed by powder X-ray diffraction. It is shown that the crystal structure of this isotypical series of materials is based on a neutral two-dimensional (2)(infinity)[Ln(H(3)tftp)(H2O)] coordination polymer placed in the ac plane of the unit cell, exhibiting a uninodal 4-connected square layered topology. It is shown that the most striking and supramolecular relevant interactions are classical O-H center dot center dot center dot O hydrogen bonds within the polymer, further contributing to the structural robustness of the layer. Prepared LnOFs were fully characterized in the solid state using elemental and thermogravimetric analysis, electron microscopy (SEM and EDS) and FT-IR spectroscopy. Compound 1 was further studied using solid-state NMR (P-31 HPDEC MAS and C-13{H-1} CP MAS) and thermodiffractometry. Photoluminescent studies have been performed on the mixed-lanthanide materials 2 and 3.
palavras-chave
COORDINATION POLYMERS; MAGNETIC-PROPERTIES; CONTRAST AGENTS; GAS-ADSORPTION; CO2 ADSORPTION; LUMINESCENCE; DESIGN; FUNCTIONALITY; CATALYSIS; SORPTION
categoria
Chemistry; Crystallography
autores
Vilela, SMF; Fernandes, JA; Ananias, D; Carlos, LD; Rocha, J; Tome, JPC; Paz, FAA
nossos autores
Duarte Ananias
Investigador Auxiliar
Filipe Alexandre Almeida Paz
Investigador Principal
João Rocha
Prof. Catedrático
José Alberto Pires Fernandes
Bolseiro de pós-Doutoramento
Luís Carlos
Professor Catedrático
Sérgio Manuel Felipe Vilela
Bolseiro de pós-Doutoramentoagradecimentos
We would like to thank Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE and Laboratario Associado Centro de Investigacao em Materiais Ceramicos e Compositos, CICECO (Pest C-CTM/LA0011/2013), the research unit QOPNA (PEst-C/QUI/UI0062/2013) for their general funding scheme. We further wish to thank FCT for the R&D project PTDC/QUI-QUI/098098/2008 (FCOMP-01-0124-FEDER-010785), and for specific funding towards the purchase of single-crystal diffractometer. We are also grateful to FCT for the PhD grant No. SFRH/BD/66371/2009 (to SMFV) and the post-doctoral grant SFRH/BPD/63736/2009 (to JAF). We also wish to thank Patricia Silva (CICECO, Dept. of Chemistry) for help with the electron microscopy EDS mapping studies.