Non-Interpenetrated Metal–Organic Frameworks Based on Copper(II) Paddlewheel and Oligoparaxylene-Isophthalate Linkers: Synthesis, Structure, and Gas Adsorption

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• 作者：Yong Yan ; Michal Juríček ; François-Xavier Coudert ; Nicolaas A. Vermeulen ; Sergio Grunder ; Anne Dailly ; William Lewis ; Alexander. J. Blake ; J. Fraser Stoddart ; Martin Schröder
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：138
• 期：10
• 页码：3371-3381
• 全文大小：713K
• ISSN：1520-5126

文摘

Two metal–organic framework materials, MFM-130 and MFM-131 (MFM = Manchester Framework Material), have been synthesized using two oligoparaxylene (OPX) tetracarboxylate linkers containing four and five aromatic rings, respectively. Both fof-type non-interpenetrated networks contain Kagomé lattice layers comprising [Cu₂(COO)₄] paddlewheel units and isophthalates, which are pillared by the OPX linkers. Desolvated MFM-130, MFM-130a, shows permanent porosity (BET surface area of 2173 m²/g, pore volume of 1.0 cm³/g), high H₂ storage capacity at 77 K (5.3 wt% at 20 bar and 2.2 wt% at 1 bar), and a higher CH₄ adsorption uptake (163 cm³(STP)/cm³ (35 bar and 298 K)) compared with its structural analogue, NOTT-103. MFM-130a also shows impressive selective adsorption of C₂H₂, C₂H₄, and C₂H₆ over CH₄ at room temperature, indicating its potential for separation of C₂ hydrocarbons from CH₄. The single-crystal structure of MFM-131 confirms that the methyl substituents of the paraxylene units block the windows in the Kagomé lattice layer of the framework, effectively inhibiting network interpenetration in MFM-131. This situation is to be contrasted with that of the doubly interpenetrated oligophenylene analogue, NOTT-104. Calculation of the mechanical properties of these two MOFs confirms and explains the instability of MFM-131 upon desolvation in contrast to the behavior of MFM-130. The incorporation of paraxylene units, therefore, provides an efficient method for preventing network interpenetration as well as accessing new functional materials with modified and selective sorption properties for gas substrates.