Synchrotron powder structure of a new layered lanthanide-organic network
authors Cunha-Silva, L; Ananias, D; Carlos, LD; Paz, FAA; Rocha, J
nationality International
journal ZEITSCHRIFT FUR KRISTALLOGRAPHIE
author keywords Powder diffraction structure analysis; X-ray diffraction; Rietveld refinement; Layered materials; Photoluminescence; Organic-inorganic hybrids
keywords CARBOXYLATE-PHOSPHONATES; HYDROTHERMAL SYNTHESIS; COORDINATION POLYMERS; DICHOTOMY METHOD; FRAMEWORK; LUMINESCENT; DIFFRACTION; DESIGN; STORAGE; SURFACE
abstract The hydrothermal synthesis and detailed structural characterisation of layered materials formulated as [Ln(H(2)cmp)] center dot xH(2)O [where H(5)cmp = (carboxymethyl)iminodi(methylphosphonic acid) and X < 1; Ln(3+) = Nd(3+) (1) and Eu(3+) (2)] are reported. Compounds were isolated as microcrystalline powders and the crystal structure of 1 was determined by ab initio methods from high-resolution synchrotron powder X-ray diffraction (PXRD) data collected at the European Synchrotron Radiation Facility (ESRF, Grenoble, France - beam lines BM01a and BM01b). The structure of 2 was refined by conventional PXRD, starting from the atomic coordinates of 1. Materials contain a single Ln3+ metal centre in highly distorted dodecahedral coordination geometry. Connectivity through H(2)cmp(3-) anionic ligands leads to undulated tapes of Ln3+ running parallel to the b-axis [closest inter-Ln distances of 4.203(3) and 4.170(3) angstrom for 1 and 2, respectively] which coalesce into layers, (2)(infinity)[Nd(H(2)cmp)], extended in the bc plane. The presence of a terminal protonated phosphonate group seems to induce the formation of the layers. Topologically, the structure is a 8-connected uninodal plane net, which can be further envisaged as two periodic self-penetrated (4,4) nets. The photophysical properties of the Eu(3+)-bearing material were studied at room temperature (with and without vacuum). The two materials have been further studied using thermogravimetric analysis (TGA), vibrational spectroscopy (ATR-FTIR) and CHN elemental analyses.
publisher OLDENBOURG VERLAG
issn 0044-2968
year published 2009
volume 224
issue 5-6
beginning page 261
ending page 272
digital object identifier (doi) 10.1524/zkri.2009.1132
web of science category Crystallography
subject category Crystallography
unique article identifier WOS:000267546200004

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