title: Synthesis and characterization of fluoride-incorporated polyoxovanadates.
abstract: The speciation studies of oxovanadates are essential to clarify their biological activities. We surveyed the distribution of oxovanadate species in the presence of halide anions with various acid concentrations in an aqueous mixed-solvent system. The presence of chloride, bromide, and iodide anions has no effects on the appearance of polyoxovanadate species observed in (51)V NMR. Those are the precedent formation of metavanadate species and decavanadates. The presence of fluoride anion during the addition of acids exhibits strong intervention in the polyoxovanadate equilibria and we found the subsequent formation of two polyoxovanadate species by (51)V NMR observation. From the estimated experimental condition, we isolated fluoride-incorporated polyoxovanadates {Et4N}4[V7O19F] and {Et4N}4[HV11O29F2], successfully. Polyanion [V7O19F](4-) is the fluoride-incorporated all V(V) state polyoxovanadate which has two different coordination environments of tetrahedral and square pyramidal vanadium units within the one anionic structural integrity. The structural gap between tetrahedral-unit-based metavanadate and octahedral-unit-based decavanadate structures may be linked by this hybrid complex.
authors.affiliation: Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kikukawa
authors.affiliation: Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
authors.forename: Taiga
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
authors.forename: Sanae
authors.initials: S
authors.lastname: Kashio
authors.affiliation: Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan. Electronic address: hayashi@se.kanazawa-u.ac.jp.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry*; D014638:Vanadates / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D014638:Vanadates; D005459:Fluorides
keywords: Anion capture; Fluoride; Polyoxovanadate; Structure transformation; Vanadium