title: Synthesis, magnetism, and electrochemistry of the Ni14- and Ni5-containing heteropolytungstates [Ni14(OH)6(H2O)10(HPO4)4(P2W15O56)4]34- and [Ni5(OH)4(H2O)4(β-GeW9O34)(β-GeW8O30(OH))]13-.
abstract: The two Ni(2+)-containing heteropolytungstates [Ni14(OH)6(H2O)10(HPO4)4(P2W15O56)4](34-) (Ni14) and [Ni5(OH)4(H2O)4(β-GeW9O34)(β-GeW8O30(OH))](13-) (Ni5) have been successfully synthesized in aqueous, basic media under conventional reaction conditions, and they were characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric and elemental analyses, electrochemistry, and magnetic studies. The cyclic voltammetry (CV) patterns of Ni14 and Ni5 showed chemically reversible multielectronic waves for slow scan time scales. For Ni14, an important acidity inversion effect between its reduced forms was observed. Magnetic studies revealed dominant ferromagnetic interactions among the nickel(II) ions in both polyanions.
authors.affiliation: Jacobs University, School of Engineering and Science, P.O. Box 750 561, 28725 Bremen, Germany.
authors.forename: Masooma
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Yixian
authors.initials: Y
authors.lastname: Xiang
authors.forename: Bassem S
authors.initials: BS
authors.lastname: Bassil
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell
authors.forename: Pedro
authors.initials: P
authors.lastname: de Oliveira
authors.forename: Bineta
authors.initials: B
authors.lastname: Keita
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kortz
mesh_terms: D060326:Chemistry Techniques, Synthetic; D004563:Electrochemistry; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D017973:Tungsten Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D017973:Tungsten Compounds; D009532:Nickel; C045951:tungstate