title: pH-controlled assembly of hybrid architectures based on Anderson-type polyoxometalates and silver coordination units.
abstract: Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host-guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24](2-) host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24](3-) clusters connected by Ag(+) cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24](3-) clusters are linked together by Ag(+) cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1-3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1-3 produces three nanocomposites 1'-3' composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1'-3' have been investigated.
authors.affiliation: College of Chemistry, Dalian University of Technology, Dalian 116023, P. R. China. anhy@dlut.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Hu
authors.forename: Haiyan
authors.initials: H
authors.lastname: An
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.forename: Jiqiu
authors.initials: J
authors.lastname: Yin
authors.forename: Huilong
authors.initials: H
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008968:Molecular Conformation; D055668:Photochemical Processes; D012235:Rhodamines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D004396:Coloring Agents; D056831:Coordination Complexes; D012235:Rhodamines; D012834:Silver; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates; C029773:rhodamine B