resumo
Two novel three-dimensional lanthanide-organic frameworks, [Er-6(OH)(8)(pydc)(5)(H2O)(3)]center dot 2.5H(2)O (1) and [Er-3(OH)(6)(pydc)Cl] (2) (pydc(2-) is the deprotonated residue of 2,5-pyridinedicarboxylic acid - 2,5-H(2)pydc), were prepared by hydrothermal synthesis into an organic matrix formed by the linker. Individual chains are disposed in the ab plane of the unit cell in a brick-wall fashion and results from the coalescence if cubane-type clusters of Er3+. Compound 2 comprises densely packed cationic [Er-3(OH)(6)Cl](n)(2n+) inorganic layers, constructed by the lateral coalescence of 1D chains identical to those found in 1. These layers are pillared by the organic linkers along the [001] direction of the unit cell yielding the crystal structure of 2. Considering the metallic tetramers and the ligands as framework nodes, compounds 1 and 2 are 7- and 2-nodal networks, respectively. While the former is unprecedented among metal-organic framework (MOF) structures, the latter is reminiscent of the known tcj/hc topological type. The crystal structures and properties of the two compounds have been investigated by (single-crystal and powder) X-ray diffraction, electron microscopy (SEM and EDX), vibrational spectroscopy, CHN elemental analyses, and thermogravimetry. The magnetic properties of 1 also have been investigated.
palavras-chave
LANTHANIDE COORDINATION POLYMERS; CAMBRIDGE STRUCTURAL DATABASE; HIGH PROTON CONDUCTIVITY; HOST-GUEST INTERACTIONS; ELECTRICAL-CONDUCTIVITY; CRYSTAL-STRUCTURE; EUROPIUM(III); CHEMISTRY; PHOTOLUMINESCENCE; COMPLEXES
categoria
Chemistry; Crystallography; Materials Science
autores
Silva, P; Cunha-Silva, L; Silva, NJO; Rocha, J; Paz, FAA
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
João Rocha
Prof. Catedrático
Nuno João Silva
Investigador PrincipalProjectos
agradecimentos
We are grateful to Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE, CICECO (PEst-C/CTM/LA0011/2011), REQUIMTE (Pest-C/EQB/LA0006/2011) for their general funding scheme. We further wish to thank FCT for funding the R&D projects PTDC/QUI-QUI/098098/2008 (FCOMP-01-0124-FEDER-010785) and PTDC/CTM/100357/2008, for specific funding towards the purchase of the single-crystal diffractometer, and for the Ph.D. scholarship No. SFRH/BD/46601/2008 (to PS) and to the Ciencia 2008 Program (NJOS).