Syntheses and structures of the MOF-type series of metal 1,4,5,8,-naphthalenetetracarboxylates M2(OH)2[C14O8H4] (Al, Ga, In) with infinite trans-connected M-OH-M chains (MIL-122)

Three new isostructural MOF-type compounds (named MIL-122) have been obtained from the hydrothermal reaction at 210 degrees C for 24 h of the 1,4,5,8-naphthalenetetracarboxylic acid with aluminum, gallium or indium source in water. The structures of the compounds M-2(OH)(2)[C14H4O8] (M = Al, Ga, In) have been solved ab initio from powder X-ray diffraction analysis using the synchrotron radiation (Soleil; station CRISTAL). The three-dimensional organic-inorganic framework exhibits infinite straight chains of metal-centered octahedra sharing trans corners linked to each other through the 1,4,5,8-naphthalenetetracarboxylate ligand. The cations Al, Ga or In, are coordinated by four oxygen atoms coming from the carboxyl groups and two bridging hydroxyl groups mu(2)-OH, located in trans position in the octahedral surrounding. The compounds characterized by thermogravimetric and thermodiffraction analyses are thermally stable up to 440,460 and 380 degrees C, for Al, Ga and In, respectively. Crystal data: monoclinic cell; P2(1)/c (n degrees 14); for MIL-122 (Al): a = 9.5174(2), b = 10.0706(1), c = 6.6465(2) angstrom, beta = 91.2614(5)degrees, V = 636.878(2) angstrom(3), Z = 2; for MIL-122 (Ga): a = 9.6501(1), b = 10.0585(1), c = 6.75069(9) angstrom, beta = 92.4786(9)degrees, V = 654.65(1) angstrom(3), Z = 2; for MIL-122 (In): a = 9.92359(5), b = 10.19765(7), c = 7.19357(4) angstrom, beta = 727.034(8)degrees, V = 727.034(8) angstrom(3), Z = 2. (C) 2009 Elsevier Masson SAS. All rights reserved.