title: High proton conductivity in a flexible, cross-linked, ultramicroporous magnesium tetraphosphonate hybrid framework.
abstract: Multifunctional materials, especially those combining two or more properties of interest, are attracting immense attention due to their potential applications. MOFs, metal organic frameworks, can be regarded as multifunctional materials if they show another useful property in addition to the adsorption behavior. Here, we report a new multifunctional light hybrid, MgH(6)ODTMP·2H(2)O(DMF)(0.5) (1), which has been synthesized using the tetraphosphonic acid H(8)ODTMP, octamethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid), by high-throughput methodology. Its crystal structure, solved by Patterson-function direct methods from synchrotron powder X-ray diffraction, was characterized by a 3D pillared open framework containing cross-linked 1D channels filled with water and DMF. Upon H(2)O and DMF removal and subsequent rehydration, MgH(6)ODTMP·2H(2)O (2) and MgH(6)ODTMP·6H(2)O (3) can be formed. These processes take place through crystalline-quasi-amorphous-crystalline transformations, during which the integrity of the framework is maintained. A water adsorption study, at constant temperature, showed that this magnesium tetraphosphonate hybrid reversibly equilibrates its lattice water content as a function of the water partial pressure. Combination of the structural study and gas adsorption characterization (N(2), CO(2), and CH(4)) indicates an ultramicroporous framework. High-pressure CO(2) adsorption data are also reported. Finally, impedance data indicates that 3 has high proton conductivity σ = 1.6 × 10(-3) S cm(-1) at T = 292 K at ~100% relative humidity with an activation energy of 0.31 eV.
authors: Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos s/n, 29071-Málaga, Spain.
authors: Rosario M P
authors: RM
authors: Colodrero
authors: Pascual
authors: P
authors: Olivera-Pastor
authors: Enrique R
authors: ER
authors: Losilla
authors: Daniel
authors: D
authors: Hernández-Alonso
authors: Miguel A G
authors: MA
authors: Aranda
authors: Laura
authors: L
authors: Leon-Reina
authors: Jordi
authors: J
authors: Rius
authors: Konstantinos D
authors: KD
authors: Demadis
authors: Bernard
authors: B
authors: Moreau
authors: Didier
authors: D
authors: Villemin
authors: Miguel
authors: M
authors: Palomino
authors: Fernando
authors: F
authors: Rey
authors: Aurelio
authors: A
authors: Cabeza
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D004553:Electric Conductivity; D008274:Magnesium / Q000737:chemistry*; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010757:Phosphorous Acids / Q000737:chemistry*; D016062:Porosity; D033362:Powder Diffraction; D011522:Protons; D013499:Surface Properties; D013696:Temperature
chemical_list: D003432:Cross-Linking Reagents; D009942:Organometallic Compounds; D010757:Phosphorous Acids; D011522:Protons; D008274:Magnesium