Co_2(O_3P-CH_2-PO_3)-H_2O: A Novel Microporous Diphosphonate with an Inorganic Framework and Hydrocarbon-Lined Hydrophobic Channels

摘要

Microporous materials are of great importance as molecular sieves, catalysts, ion-exchangers, and sensor materials. Extensive exploration of new systems and new methods of synthesis has led to discoveries of novel materials with controlled pore sizes,better acidity, and better thermal stability. Nevertheless, despite the large number of different microporous compounds, all of them, with only two exceptions, have hydrophilic channels. The two exceptions are the methylphosphonates of aluminum and copper. Such phosphonates and diphosphonates of the transition as well as main group metals have also received much attention during the last few years. These are built of inorganic layers or chains that are either "coated" by the phos-phonate and are held together by weak intermolecular forces. or are linked covalently through diphosphonate groups. Many of the diphosphonates and one monophosphonate. an aminoethylphosphonate, mimic open-framework structures with hydrophobic channels but their "frameworks" contain organic interchain or interlayer links. The Al- and Cu-methylphosphonates are the only phosphonates that are microporous, have three-dimensional inorganic-only backbones, that is composed of a metal-oxygen-phosphorus network, and contain hydrophobic channels.