Crystalline oxyfluorinated open-framework compounds: Silicates, metal phosphates, metal fluorides and metal-organic frameworks (MOF)

详细信息	查看全文 | 推荐本文 |

• 作者：Thierry Loiseau ; Gé ; rard Fé ; rey
• 关键词：Microporous compounds ; Fluorine ; Zeolites ; Aluminum phosphates ; Gallium phosphates ; Metal-organic frameworks
• 刊名：Journal of Fluorine Chemistry
• 出版年：2007
• 期刊代码：52_00221139
• 类别：ch
• 出版时间：April 2007
• 卷：128
• 期：4
• 页码：413-422
• 文件大小：777 K

摘要

This contribution is dedicated to a short overview on the utilization of fluorine for the preparation of crystalline microporous frameworks including different families of solids: zeolites, metal phosphates and metal-organic frameworks (MOF-type). Beside the silicates compounds, this presentation is focused on the different types of fluorinated aluminum or gallium phosphates hydrothermally obtained in the presence of organic structure-directing agent or templates. The structural features of aluminum fluorides synthesized with amines are also detailed as well as the influence of fluorine in the synthesis of the metal-organic frameworks involving trivalent metals. The role of fluorine is described for the hydrothermal synthesis of the different classes of materials. Fluorine is known for playing the role of mineralizing agent and favors the formation of well crystalline phases. The use of HF modifies the pH of the reaction, which allows for the insertion of additional metallic cations on the mineral network. From the structural point of view, fluoride anions can be located within small cavities of the 3D framework and interactions with metals T (T = Si, Al, Ga, …) are often observed, resulting in the coordination change (from tetrahedral unit TO₄ to trigonal bipyramid TO₄F or octahedron TO₄F₂). Several configurations are found for fluorine and it seems to favor the stabilization of the specific cubane-like building unit (D4R), in which it is trapped, or participates to the coordination sphere of the metal atoms with bridging or terminal bondings. In general, new three-dimensional topologies with extra-large pores are obtained. The synthesis of purely aluminum fluorides with structure-directing agent is considered but only molecular or low-dimensional structures (chain-like or layered) compounds have been described. Fluorine is also used as a mineralizing agent for the preparation of well crystalline porous aluminum or chromium carboxylates and it was observed to partly substitute the aquo ligands in the giant pore of the compound MIL-100.