title: An unusual fan-type polyanion with a silver cation located at the axial center, [AgAsIII2(AsIIIAsVMo4O18(OH)2)3]11-.
abstract: A new type of polyoxomolybdate containing mixed-valence arsenic, [AgAs(III)(2)(As(III)As(V)Mo(4)O(18)(OH)(2))(3)](11-) (1), has been synthesized. Single-crystal X-ray analysis was carried out on (NH(4))(5)(C(2)H(9)N(2))(4.5)H(1.5)[AgAs(III)(2)(As(III)As(V)Mo(4)O(18)(OH)(2))(3)]·14H(2)O (1a) and (NH(4))(11)[AgAs(III)(2)(As(III)As(V)Mo(4)O(18)(OH)(2))(3)]·16H(2)O (1b). The polyanion is composed of three unprecedented [As(III)As(V)Mo(4)O(18)(OH)(2)](6-) subunits linked together by two AsO(3) trigonal-pyramidal structures from both sides via sharing six bridging oxygen atoms, and a silver cation is enclosed in the center of the polyanion and coordinated by three As atoms with the As-Ag-As bond angle of 120°, to lead to a fan-like structure with an approximative C(3h) symmetry. The polyanion was also characterized by IR, X-ray photoelectron spectroscopy and thermogravimetry-differential scanning calorimetry. The stability of [AgAs(III)(2)(As(III)As(V)Mo(4)O(18)(OH)(2))(3)](11-) in an aqueous solution was investigated by electronic absorbance spectroscopy and electrospray ionization mass spectrometry, and the possible disaggregation mechanism of the polyanion is proposed.
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Department of Chemistry, Northwest University, Xi'an, 710069, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.forename: Qi
authors.initials: Q
authors.lastname: Xue
authors.forename: Suotian
authors.initials: S
authors.lastname: Min
authors.forename: Yanping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huaiming
authors.initials: H
authors.lastname: Hu
authors.forename: Shengli
authors.initials: S
authors.lastname: Gao
authors.forename: Ganglin
authors.initials: G
authors.lastname: Xue
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002412:Cations / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry*; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry; D000099294:Polyoxometalates
chemical_list: D001151:Arsenic; D002412:Cations; D056831:Coordination Complexes; D008982:Molybdenum; D000071228:Polyelectrolytes; D011108:Polymers; D012834:Silver; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates