title: Synthesis, water adsorption, and proton conductivity of solid-solution-type metal-organic frameworks Al(OH)(bdc-OH)(x)(bdc-NH2)(1-x).
abstract: Mixed-ligand metal-organic frameworks Al(bdc-OH)(x)(bdc-NH2)(1-x) (H2bdc-NH2 = aminoterepthalic acid, H2bdc-OH = hydroxyterephthalic acid) were synthesized and their water adsorption behavior and proton conductivity were investigated. All obtained compounds were isostructural to MIL-53 (MIL = Materials of Institut Lavoisier) according to XRD measurements under ambient humidity conditions, and were also found to be single phase across the whole mixing ratio from the XRD measurements under humidified conditions. This result clearly shows that all compounds are a solid-solution-type mixture of ligands. MIL-53-NH2 adsorbs one water molecule per formula with humidification whereas MIL-53-OH adsorbs five water molecules. The mixing ratio of the ligands in Al(OH)(bdc-OH)(x)(bdc-NH2)(1-x) affected the gate-opening pressure for water adsorption and total water uptake. Proton conductivity of these compounds largely depends on the adsorbed amount of water, which indicates that the proton conductivity of these compounds depends strongly on the hydrogen-bond network of the conducting media.
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecyo, Sakyo-ku, Kyoto 606-8502 (Japan), Fax: (+81) 757534035; Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395(Japan). teppei343@gmail.com.
authors.forename: Teppei
authors.initials: T
authors.lastname: Yamada
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shirai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
mesh_terms: D000327:Adsorption; D017607:Aluminum Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D014867:Water
keywords: adsorption; metal-organic frameworks; proton transport; solid solutions