Germanate with Three-Dimensional 12 x 12 x 11-Ring Channels Solved by X-ray Powder Diffraction with Charge-Flipping Algorithm

A new open-framework germanate, denoted as GeO-JU90, was prepared by the hydrothermal synthesis method using 1,5-bis(methylpyrrolidinium)pentane dihydroxide as the organic structure-directing agent (SDA). The structure of GeO-JU90 was determined from synchrotron X-ray powder diffraction (XRPD) data using the charge-flipping algorithm. It revealed a complicated framework structure containing 11 Ge atoms in the asymmetric unit. The framework is built of 7-connected Ge-7 clusters and additional tetrahedral GeO3(OH) units forming a new three-dimensional interrupted framework with interesting 12 X 12 X 11-ring intersecting channels. The Ge K-edge extended X-ray absorption fine structure (EXAFS) analysis was performed to provide the local structural information around Ge atoms, giving rise to a first-shell contribution from about 4.2(2) O atoms at the average distance of 1.750(8) angstrom. The guest species subsequently determined by the simulated annealing method from XRPD data combining with other characterization techniques, e.g., C-13 NMR spectroscopy, infrared spectroscopy (FTIR), compositional analyses, and thermogravimetric analysis (TGA). Crystallographic data vertical bar(C15N2H32)(NH4)vertical bar[Ge11O21.5(OH)(4)], orthorhombic Ama2 (No. 40), a = 37.82959 angstrom, b = 15.24373 angstrom, c = 12.83659 angstrom, and Z = 8.Chemistry, Inorganic & NuclearSCI(E)2ARTICLE1810238-102445