Interconvertable modular framework and layered lanthanide(III)-etidronic acid coordination polymers

Isostructural modular microporous Na-2[Y(hedp)(H2O)(0.67)] and Na-4[Ln(2)(hedP)(2)(H2O)(2)]center dot nH(2)O (Ln = La, Ce, Nd, Eu, Gd, Tb, Er) framework-type, and layered orthorhombic [Eu(H(2)hedp)(H2O)(2)]center dot H2O and Na-0.9[Nd0.9Ge0.10(Hhedp)(H2O)(2)], monoclinic [Ln[H(2)hedp)(H2O)]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)(H2O)(2)]center dot H2O 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)(H2O)2]center dot nH(2)O, affords layered [Tb(H(2)hedp) (H2O)]center dot 3H(2)O, whereas layered [Tb(H(2)hedp)(H2O)(2)]center dot H2O reacts-with sodium chloride yielding a material similar to Na-4[Tb-2(hedP)(2)(H2O)(2)]center dot nH(2)O. In layered [Y(H(2)hedp)(H2O)]center dot 3H(2)O, noncoordinated water molecules are engaged in cooperative waterto-water hydrogen-bonding interactions, leading to the formation of a (H2O)(13) cluster, which is the basis of an unprecedented two-dimensional water network present in the interlayer space.