Syntheses and structures of two new 3D open-framework germanates constructed from Ge9O18(OH)4 clusters

Two new open-framework germanates, [Cd-2(C2N2H8)(3)][Ge9O18(OH)(4)] (1) and (CsN4H26)[Ge9O18(OH)(4)] (2), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group, Pbca, with a = 14.318(3), b = 13.106(3), c = 14.580(3) Angstrom, V = 2736.0(9) Angstrom(3), Z = 4. The compound is the first organically templated cadmium germanate. The structure of 1 is constructed from two distinct motifs, a body-centered [Ge9O18(OH)(4)] cluster and a cadmium complex [Cd-2(C2N2H8)(3)O-6], which integrate to generate a 3D architecture with neutral framework. The structures of 2 is closely related to that of 1 and has identical Ge9O18(OH)(4) clusters. It crystallizes in the orthorhombic space group, Pbca, with a = 14.158(3), b = 13.213(3), c = 14.553(3) Angstrom, V = 2722.5(9) Angstrom(3), Z = 4. The connectivity between the Ge-9 clusters result in a 3D open-framework structure. The quadruply protonated N,N'-bis(3-aminopropyl)ethylene diamine molecules are located in the free voids and interact with the macroanionic inorganic framework by extensive hydrogen bonds. (C) 2004 Elsevier Inc. All rights reserved.