Investigation of the GeO<sub>2</sub>-1,6-Diaminohexane-Water-Pyridine-HF Phase Diagram Leading to the Discovery of Two Novel Layered Germanates with Extra-Large Rings
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posted on 2011-01-03, 00:00 authored by Bing Guo, Andrew K. Inge, Charlotte Bonneau, Junliang Sun, Kirsten E. Christensen, Zhong-Yong Yuan, Xiaodong ZouThe systematic exploration of the phase diagram of the GeO<sub>2</sub>-1,6-diaminohexane-water-pyridine-HF system has allowed the identification of specific roles of the HF, H<sub>2</sub>O contents, and HF/H<sub>2</sub>O ratio in the formation of Ge<sub>7</sub>X<sub>19</sub> (Ge<sub>7</sub>), Ge<sub>9</sub>X<sub>25−26</sub> (Ge<sub>9</sub>), and Ge<sub>10</sub>X<sub>28</sub> (Ge<sub>10</sub>) clusters (X = O, OH, F). This work has led to the discovery of two novel structures with extra-large 18-membered rings accommodating 1,6-diaminohexane (DAH): SU-63, |1.5H<sub>2</sub>DAH|[Ge<sub>7</sub>O<sub>14</sub>X<sub>3</sub>]·2H<sub>2</sub>O, a layered germanate constructed from Ge<sub>7</sub> clusters with the Kagomé topology, and SU-64, |11H<sub>2</sub>DAH|[Ge<sub>9</sub>O<sub>18</sub>X<sub>4</sub>][Ge<sub>7</sub>O<sub>14</sub>X<sub>3</sub>]<sub>6</sub>·16H<sub>2</sub>O, a germanate built of two-dimensional slabs containing both Ge<sub>7</sub> and Ge<sub>9</sub> clusters (X = OH or F). We also put SU-64 in context with previously reported cluster germanate compounds with related topologies by means of a simple crystal deconstruction study.
