abstract
Isostructural modular microporous Na(2)[Y(hedp)(H(2)O)(0.67)] and Na(4)[Ln(2)(hedP)(2)(H(2)O)(2)]center dot nH(2)O (Ln = La, Ce, Nd, Eu, Gd, Tb, Er) framework-type, and layered orthorhombic [Eu(H(2)hedp)(H(2)O)(2)]center dot H(2)O and Na(0.9)[Nd(0.9)Ge(0.10)(Hhedp)(H(2)O)(2)], monoclinic [Ln[H(2)hedp)(H(2)O)]center dot 3H(2)O (Ln = Y, Tb), and triclinic [Yb(H(2)hedp)]center dot H 20 coordination polymers based on etidronic acid (H5hedp) have been prepared by hydrothermal synthesis and characterized structurally by (among others) single-crystal and powder X-ray diffraction and solid-state NMR. The structure of the framework materials comprises eight-membered ring channels filled with Na(+) and both free and lanthanide-coordinated water molecules, which are removed reversibly by calcination at 300 degrees C (structural integrity is preserved up to ca. 475 degrees C), denoting a clear zeolite-type behavior. Interesting photoluminescence properties, sensitive to the hydration degree, are reported for Na(4)[Eu(2)(hedP)(2)(H(2)O)(2)]center dot H(2)O and its fully dehydrated form. The 3D framework and layered materials are, to a certain extent, interconvertable during the hydrothermal synthesis stage via the addition of HCl or NaCl: of the 3D framework Na(4)[Tb(2)(hedP)(2)(H(2)O)2]center dot nH(2)O, affords layered [Tb(H(2)hedp) (H(2)O)]center dot 3H(2)O, whereas layered [Tb(H(2)hedp)(H(2)O)(2)]center dot H(2)O reacts-with sodium chloride yielding a material similar to Na(4)[Tb(2)(hedP)(2)(H(2)O)(2)]center dot nH(2)O. In layered [Y(H(2)hedp)(H(2)O)]center dot 3H(2)O, noncoordinated water molecules are engaged in cooperative waterto-water hydrogen-bonding interactions, leading to the formation of a (H(2)O)(13) cluster, which is the basis of an unprecedented two-dimensional water network present in the interlayer space.
keywords
METAL-ORGANIC FRAMEWORK; EFFECTIVE IONIC-RADII; X-RAY-DIFFRACTION; HIGH-SURFACE-AREA; HYDROTHERMAL SYNTHESIS; MAGNETIC-PROPERTIES; GIANT PORES; STRUCTURAL-CHARACTERIZATION; MOLECULAR-CRYSTALS; POWDER DIFFRACTION
subject category
Chemistry
authors
Shi, FN; Cunha-Silva, L; Ferreira, RAS; Mafra, L; Trindade, T; Carlos, LD; Paz, FAA; Rocha, J
our authors
Fa-Nian Shi
Researcher
Filipe Alexandre Almeida Paz
Principal Researcher
João Rocha
Full Professor
Luís Carlos
Full professor
Luís Mafra
Principal Researcher
Maria Rute de Amorim e Sá Ferreira André
Full professor