Structural Study of Hydrated/Dehydrated Manganese Thiophene-2,5-diphosphonate Metal Organic Frameworks, Mn2(O3P鈥揅4H2S鈥揚O3)路2H2O

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• 作者：Jean-Michel Rueff ; Olivier Perez ; Alain Pautrat ; Nicolas Barrier ; Gary B. Hix ; Sylvie Hernot ; H茅l猫ne Couthon-Gourv猫s ; Paul-Alain Jaffr猫s
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：October 1, 2012
• 年：2012
• 卷：51
• 期：19
• 页码：10251-10261
• 全文大小：604K
• 年卷期：v.51,no.19(October 1, 2012)
• ISSN：1520-510X

文摘

Synthesis of thiophene-2,5-diphosphonic acid 2 is reported, and its use for synthesis of the original pristine materials Mn₂(O₃P鈥揅₄H₂S鈥揚O₃)路2H₂O 3 is reported. The structure of material 3 has been fully resolved from single-crystal X-ray diffraction. Mn₂(O₃P鈥揅₄H₂S鈥揚O₃)路2H₂O 3 crystallizes in a monoclinic cell (space group P2) with the following parameters: a = 11.60(1) 脜, b = 4.943(5) 脜, c = 19.614(13) 脜, 尾 = 107.22掳. A noticeable feature of the structure of compound 3 is the orientation of the thiophene heterocycles that adopt two different orientations in two successive layers (along c). Thermal analysis of compound 3 indicates that the water molecules are easily removed from 160 to 230 掳C while the dehydrated structure is stable up to 500 掳C. The dehydrated compound obtained from 3 can be rehydrated to give the polymorphic compound Mn₂(O₃P鈥揅₄H₂S鈥揚O₃)路2H₂O 4, which crystallizes in an orthorhombic cell (space group Pnam) with the following parameters: a = 7.5359(3) 脜, b = 7.5524(3) 脜, c = 18.3050(9) 脜. The main difference between the structures of 3 and 4 arises from both the orientation of the thiophene rings (herringbone-type organization in 4) and the structure of the inorganic layers. The thiophene-2,5-diphosphonic acid moieties engaged in materials 3 and 4 adopt a different orientation likely due to rotation around the P鈥揅 bonds and via the dehydrated state 5, which is likely more flexible than the hydrated states. Study of the magnetic properties performed on compound 3 and 4 and on the dehydrated compounds Mn₂(O₃P鈥揅₄H₂S鈥揚O₃) 5 complemented by the structural study has permitted us to characterize the antiferromagnetic ground state of sample 3, a weak ferromagnetic component in sample 4, and complete paramagnetic behavior in sample 5.