Characterisation and properties of the n

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• 作者：Martin P. Attfield ; Carlos Mendieta-Tan ; Zhanhui Yuan ; William Clegg
• 关键词：Aluminium ; Diphosphonate ; Framework ; Microporous ; Hybrid ; Metal organic
• 刊名：Solid State Sciences
• 出版年：2008
• 出版时间：September 2008
• 年：2008
• 卷：10
• 期：9
• 页码：1124-1131
• 全文大小：856 K

文摘

A combination of techniques has been used to fully determine the structure and properties of Al₂[O₃PC₄H₈PO₃](H₂O)₂F₂·2H₂O (monoclinic, P2₁/m, a = 4.96926(6) Å, b = 12.0013(1) Å, c = 10.7440(2) Å, β = 94.058(1)°, Z = 2, R_p = 0.0732, R_wp = 0.0939), the n = 4 member of the framework aluminium alkylenediphosphonate Al₂[O₃PC_nH_2nPO₃](H₂O)₂F₂ series. The combination of thermogravimetric and thermodiffraction data and the structure determination of the partially dehydrated structure, Al₂[O₃PC₄H₈PO₃](H₂O)₂F₂·0.17(1)H₂O (monoclinic, P2₁/m, a = 4.9392(3) Å, b = 12.1867(4) Å, c = 10.7830(5) Å, β = 94.767(3)°, Z = 2, R_p = 0.0839, R_wp = 0.1121), indicate that the framework structure is stable to, and remains unchanged, with respect to the loss of the extra-framework water molecules but not the framework water molecules. This behaviour is in stark contrast to the n = 3 member of the Al₂[O₃PC_nH_2nPO₃](H₂O)₂F₂ series, Al₂[O₃PC₃H₆PO₃](H₂O)₂F₂·H₂O, for which the combination of thermogravimetric and thermodiffraction data indicates that the framework structure contracts during the loss of the extra-framework water molecules before collapsing after loss of the framework water molecules. The formation of the n = 4 member of the series indicates that the design of the alkyl chain can be used to successfully control aspects of the pore volume within this family of materials and comparison of the dehydration behaviour of the n = 3 and n = 4 members of the series indicates that related materials containing channels housing the same number of water molecules exhibit different dehydration behaviour depending on the stacking of the constituent inorganic layers within the material.