Structural Variability in Multifunctional Metal Xylenediaminetetraphosphonate Hybrids

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• 作者：Rosario M. P. Colodrero ; Giasemi K. Angeli ; Montse Bazaga-Garcia ; Pascual Olivera-Pastor ; Didier Villemin ; Enrique R. Losilla ; Estefania Q. Martos ; Gary B. Hix ; Miguel A. G. Aranda ; Konstantinos D. Demadis ; Aurelio Cabeza
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：August 5, 2013
• 年：2013
• 卷：52
• 期：15
• 页码：8770-8783
• 全文大小：758K
• 年卷期：v.52,no.15(August 5, 2013)
• ISSN：1520-510X

文摘

Two new families of divalent metal hybrid derivatives from the aromatic tetraphosphonic acids 1,4- and 1,3-bis(aminomethyl)benzene-N,N鈥?bis(methylenephosphonic acid), (H₂O₃PCH₂)₂鈥揘鈥揅H₂C₆H₄CH₂鈥揘(CH₂PO₃H₂)₂ (designated herein as p-H₈L and m-H₈L) have been synthesized by crystallization at room temperature and hydrothermal conditions. The crystal structures of M[(HO₃PCH₂)₂N(H)CH₂C₆H₄CH₂N(H)(CH₂PO₃H)₂(H₂O)₂]路2H₂O (M = Mg, Co, and Zn), M鈥?p-H₆L), and M[(HO₃PCH₂)₂N(H)CH₂C₆H₄CH₂N(H)(CH₂PO₃H)₂]路nH₂O (M = Ca, Mg, Co, and Zn and n = 1鈥?.5), M鈥?m-H₆L), were solved ab initio by synchrotron powder diffraction data using the direct methods and subsequently refined using the Rietveld method. The crystal structure of the isostructural M鈥?p-H₆L) is constituted by organic鈥搃norganic monodimensional chains where the phosphonate moiety acts as a bidentate chelating ligand bridging two metal octahedra. M鈥?m-H₆L) compounds exhibit a 3D pillared open-framework with small 1D channels filled with water molecules. These channels are formed by the pillaring action of the organic ligand connecting adjacent layers through the phosphonate oxygens. Thermogravimetric and X-ray thermodiffraction analyses of M鈥?p-H₆L) showed that the integrity of their crystalline structures is maintained up to 470 K, without significant reduction of water content, while thermal decomposition takes place above 580 K. The utility of M鈥?p-H₆L) (M = Mg and Zn) hybrid materials in corrosion protection was investigated in acidic aqueous solutions. In addition, the impedance data indicate both families of compounds display similar proton conductivities (蟽 9.4 脳 10^鈥? S路cm^鈥?, at 98% RH and 297 K), although different proton transfer mechanisms are involved.