High-Throughput Aided Synthesis of the Porous Metal−Organic Framework-Type Aluminum Pyromellitate, MIL-121, with Extra Carboxylic Acid Functionalization

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• 作者：Christophe Volkringer ; Thierry Loiseau ; Nathalie Guillou ; Grard Frey ; Mohamed Haouas ; Francis Taulelle ; Erik Elkaim ; Norbert Stock
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：November 1, 2010
• 年：2010
• 卷：49
• 期：21
• 页码：9852-9862
• 全文大小：1291K
• 年卷期：v.49,no.21(November 1, 2010)
• ISSN：1520-510X

文摘

A new porous metal−organic framework (MOF)-type aluminum pyromellitate (MIL-121 or Al(OH)[H₂btec]·(guest), (guest = H₂O, H₄btec = pyromellitic acid) has been isolated by using a high-throughput synthesis method under hydrothermal conditions. Its structure was determined from powder X-ray diffraction analysis using synchrotron radiation (Soleil, France) and exhibits a network closely related to that of the MIL-53 series. It is a three-dimensional (3D) framework containing one-dimensional (1D) channels delimited by infinite trans-connected aluminum-centered octahedra AlO₄(OH)₂ linked through the pyromellitate ligand. Here the organic ligand acts as tetradendate linker via two of the carboxylate groups. The two others remain non-bonded in their protonated form, and this constitutes a rare case of the occurrence of both bonding and non-bonding organic functionalities of the MOF family. The non-coordinated −COOH groups points toward the channels to get them an open form configuration. Within the tunnels are located unreacted pyromellitic acid and water species, which are evacuated upon heating, and a porous MIL-121 phase is obtained with a Brunauer−Emmett−Teller (BET) surface area of 162 m² g⁻¹. MIL-121 has been characterized by IR, thermogravimetry (TG) analyses, and solid state NMR spectroscopy employing a couple of two-dimensional (2D) techniques such as ¹H-¹H SQ-DQ BABA, ¹H-¹H SQ-SQ RFDR, ²⁷Al{¹H} CPHETCOR and ²⁷Al MQMAS.