Solvent-Induced Structural Dynamics in Noninterpenetrating Porous Coordination Polymeric Networks

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• 作者：Raghavender Medishetty ; Daram Jung ; Xiaokai Song ; Dongwook Kim ; Shim Sung Lee ; Myoung Soo Lah ; Jagadese J. Vittal
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：March 18, 2013
• 年：2013
• 卷：52
• 期：6
• 页码：2951-2957
• 全文大小：395K
• 年卷期：v.52,no.6(March 18, 2013)
• ISSN：1520-510X

文摘

Three novel soft porous coordination polymer (PCP) or metal鈥搊rganic framework (MOF) compounds have been synthesized with a new rigid ligand N-(4-pyridyl)-1,4,5,8-naphathalenetetracarboxymonoimide (PNMI) by partial hydrolysis of N,N鈥?/i>-di-(4-pyridyl)-1,4,5,8-naphthalenete-tracarboxydiimide (DPNI) during solvothermal reactions with Zn(II), Cd(II), and Mn(II) salts, and they are [Zn(PNMI)]路2DMA (1路2DMA, 1a), [Cd(PNMI)]路0.5DMA路5H₂O (2路0.5DMA路5H₂O), and [Mn(PNMI)]路0.75DMF (3路0.75DMF). The structure of 1 is based on paddle-wheel secondary building unit (SBU) with a 3,6-connected rtl net topology, whereas 2 and 3 are isotypical but the M(O₂C鈥揅)₂ fragments aggregate in one-dimension and the overall connectivity is the same rtl net topology. All these three MOFs have one-dimensional rhombic channels filled with guest molecules. The guest molecules in 1a can be exchanged with EtOH in a single-crystal to single-crystal (SCSC) manner to 1路1.25EtOH路0.375H₂O (1b). Further, the guest molecules in 1b can be replaced with ethylene glycol, triethylene glycol and allyl alcohol without destroying its single crystal nature. These guest exchanges are accompanied by reduction in volume of the unit cell up to 16%, as well as the void volume up to 33.1%. Similarly, triethylene glycol (TEGly) selectively exchanges EtOH in a mixture of the above solvents, which might be the result of correct fit of the hydrogen-bonded TEGly dimer in the channel of 1. While activated 1 and 3 exhibit no uptake of N₂ and H₂ at 1 bar and 77 K and very low uptake of CO₂ gas at 1 bar and 196 K, activated 2 shows selective CO₂ uptake, 278 cm²路g^鈥?, over N₂ and H₂ at 1 bar and 196 K, which corresponds to 5.87 molecules of CO₂ per formula unit of 2.