Soluble Metal-Organic Frameworks: Dissolution/Reassembly towards the Structural Rearrangement of Porous Cobalt(II)- and Nickel(II)–Carboxylate Coordination Polymers

• Main Authors: Miao-Tzu Ding, 丁妙慈
• Other Authors: Kuang-Lieh Lu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/40897218316524320914

碩士 === 國立中央大學 === 化學研究所 === 96 === The goal of this study was to develop a self-assembly synthetic strategy for the preparation of metal–organic coordination polymers using benzene-1,2,4,5-tetracarboxylic acid (H4btec) and transition-metal ions (CoII, NiII). Four three-dimensional, soluble, porous metal–organic coordination networks {K2[Co3(btec)2(H2O)4]∙6H2O}n (1•6H2O), {K2[Ni3(btec)2(H2O)4]•4H2O}n (2•4H2O), {Cs2[Co3(btec)2(H2O)4]•3H2O}n (3•3H2O), and {Cs2[Ni3(btec)2(H2O)4]•3H2O}n (4•3H2O) with near identical structural features were hydrothermally prepared. These structures adopt a (4,8)-connected net consisting of a four-connected square-planar node of a btec4－ ligand and an eight-connected node of trinuclear clusters M3(O2C)8(H2O)4. These three-dimensional frameworks possess hydrophilic channels, where the alkali metal ions (KI or CsI) and free water molecules reside. Ion-exchange studies, by treating 1～4 in an aqueous solution of alkali chloride (LiCl, NaCl, CsCl and KCl), revealed that a surprisingly dissolution/reassembly process occurred, leading to the rearrangement of metal–carboxylate building blocks and the formation of new metal–carboxylate species (5～13). The structural transformations were confirmed by single-crystal and powder X-ray diffraction (PXRD) data