Ndx[O2C–(CH2)3–CO2]y(H2O)z. mH2O framework structures features.

BRUSAU E. V., NARDA G. E., POZZI C. G., ECHEVERRÍA G., ELLENA J. A., PUNTE G.

La Plata, Argentina

Workshop; Hyperfine Interactions at La Plata; 2005

Laboratorio de Espectroscopía Nuclear e interacciones Hiperfinas. Dpto de Física. Fac. de Cs. Exactas INLP, IFLP (CONICET)

Ndx[O2C–(CH2)3–CO2]y(H2O)z. mH2O framework structures features. Brusau E. V.1, Narda G. E.1, Pozzi C. G.2, Echeverría G.2,3, Ellena J. A.4, Punte G.2 1Area de Química General e Inorgánica “Dr. G. F. Puelles”, Facultad de Química, Bioquímica y Farmacia, UNSL, Argentina. 2 LANADI e IFLP, Departamento de Física, Facultad de Cs. Exactas,3 Facultad de Ingeniería, UNLP, Argentina.3 Instituto de Física São Carlos, Universidade de São Paulo, SP, Brazil. An intense activity is developed at present to obtain open hybrid frameworks because of their many applications; mainly those ones related to the likelihood of inducing incremental modulation of their pores sizes. Besides, 3D hybrid solids may build-in inorganic networks of different dimensionalities, opening the possibility of designing materials with optical or magnetic properties when suitable metals are included. Here, we will present an investigation on the influence of the synthesis conditions on the structural properties and thermal stability of Nd(III) glutarates hydrates. It has been claimed in the literature that the hydrothermal route (or at least temperatures above ambient) are necessary to produce hybrid frameworks involving aliphatic dicarboxylates. We present two different hydrates prepared from solutions at room temperature. One of the frameworks observed shows pores similar to that ones found by other authors [1], some small differences observed (reflected in unit cell parameters changes) can be attributed to variations in the number of guest water molecules within them. The other, presents a novel framework structure where metal cations coordinate with an additional water molecule. The conformation of the labile glutarate anions is modified by this extra water causing enlargement of pores size in which higher hydration water molecules are accommodated. Both, the IR and Raman spectra of these hydrates reflect the complexity of their crystal structures, particularly the interactions involving the water molecules located in different positions in the framework, as well as both binding modes found for the OCO groups. The thermal studies are in agreement with the structural findings and the anhydrous compounds are stable up to ca. 723 K. [1] T. Glowiak, Dao-Cong-Ngoan and J. Legendziewicz, Acta Crystallogr. C42, 1494, (1986). Keywords: framework structures, hybrid materials, rare earth glutarates