MAGNETIC MATERIALS

Magnetism

Polyoxotungstates are ideal candidates for the incorporation of multinuclear magnetic transition metal clusters. This is largely due to the existence of a large number of vacant, stable polytungstate precursors (as opposed to polymolybdates or polyvanadates). The number of vacant sites in a single lacunary polytungstate can range from 1 (e.g. [SiW11O39]8−) to 2 (e.g. [γ- SiW10O36]8−), to 3 (e.g. [P2W15O56]12−), to 6 (e.g. [H2P2W12O48]12−) all the way to 20 (e.g. [H8P8W48O184]32−). Formation of dimeric, trimeric, tetrameric, etc. assemblies can therefore allow for encapsulation of a large number of spin-coupled magnetic centers (d- or f-block), usually bridged via μ2-oxo/hydroxo/aqua groups. This means that many different shapes, sizes and types of magnetic clusters can be stabilized by polytungstate ligands. Furthermore, the diamagnetic tungsten-oxo capping fragments isolate the respective magnetic clusters so well from each other that intermolecular interactions are usually negligible. This means that detailed and subtle magnetic phenomena can be studied strictly on the molecular level.

Magnetic POMs have also provided convincing experimental evidence for the occurrence of anisotropic exchange interactions in exchange coupled clusters. Thus, inelastic neutron scattering studies on POMs containing a Co3 cluster showed not only that anisotropic exchange interactions definitively occur in these systems, but also that the anisotropic exchange interaction tensorsmay be nonparallel. Antisymmetric exchange interactionswere also found in Cu3 POMs, and in the previouslymentioned {V6Mo57} cluster. Generally speaking, direct evidence for antisymmetric exchange in exchange coupled clusters is quite scarce. Nickel(II) containing polytungstates were investigated in detail using inelastic neutron scattering in addition to magnetic measurements, which enabled the determination of single-ion anisotropies as well as isotropic exchange interaction parameters.


Selected Publications

  • CrIII-substituted Heteropoly-16-Tungstates [CrIII2(B-β- XIVW8O31)2]14- (X = Si, Ge): Magnetic, Biological, and Electrochemical Studies
    Liu, W.; Al-Oweini, R.; Meadows, K.; Bassil, B. S.; Lin, Z.; Christian, J. H.; Dalal, N. S.; Bossoh, A. M.; Mbomekallé, I. M.; de Oliveira, P.; Iqbal, J.; Kortz, U. Inorg. Chem. 2016, 55, 10936−10946. [Read Online]
  • Mixed-Valent Mn16-Containing Heteropolyanions: Oxidation State Tuning and Resulting Physicochemical Properties
    Haider, A.; Ibrahim, M.; Bassil, B. S.; Carey, A.M.; Nguyen Viet, A.; Xing, X.; Ayass, W. W.; Miñambres, J. F.; Liu, R.; Zhang, G.; Keita, B.; Mereacre, V.; Powell, A. K.; Balinski, K.; N’Diaye, A. T.; Kuepper, K.; Chen, H.-Y.; Stimming, U.; Kortz, U. Inorg. Chem. 2016, 55 , 2755-2764[Read Online]
  • Heptanickel(II) Double-Cubane Core in Wells-Dawson Heteropolytungstate, [Ni7(OH)6(H2O)6(P2W15O56)2]16-
    Bassil, B. S.; Xiang, Y.; Haider, A.; Hurtado, J.; Novitchi, G.; Powell, A. K.; Bossoh, A. M.; Mbomekallé, I. M.; de Oliveira, P.; Kortz, U. Chem. Commun. 2016, 52, 2601-2604.[Read Online]
  • Ln12-Containing 60-Tungstogermanates: Synthesis, Structure, Luminescence, and Magnetic Studies
    Wang, K.-Y.; Bassil, B. S.; Lin, Z.; Römer, I.; Vanhaecht, S.; Parac-Vogt, T. N.; de Pipaón, C. S.; Galán-Mascarós, J. R.; Fan, L.; Cao, J.; Kortz, U. Chem. Eur. J. 2015, 21, 18168-18176. [Read Online] 
  • Molecular spin qubits based on lanthanide ions encapsulated in cubic polyoxopalladates: design criteria to enhance quantum coherence
    Baldoví, J. J.; Rosaleny, L. E.; Ramachandran, V.; Christian, J.; Dalal, N. S.; Clemente-Juan, J. M.; Yang, P.; Kortz, U.; Gaita-Ariño, A.; Coronado, E. Inorg. Chem. Front. 2015, 2, 893-897. [Read Online]
  • Synthesis, Detailed Characterization, and Theoretical Understanding of Mononuclear Chromium(III)-Containing Polyoxotungstates [CrIII(HXVW7O28)2]13- (X = P, As) with Exceptionally Large Magnetic Anisotropy
    Liu, W.; Christian, J. H.; Al-Oweini, R.; Bassil, B. S.; van Tol, J.; Atanasov, M.; Neese, F.; Dalal, N. S.; Kortz, U. Inorg. Chem. 2014, 53, 9274-9283. [Read Online]
  • Synthesis and Characterization of Multinuclear Manganese-Containing Tungstosilicates
    Al-Oweini, R.; Bassil, B. S.; Friedl, J.; Kottisch, V.; Ibrahim, M.; Asano, M.; Keita, B.; Novitchi, G.; Lan, Y.; Powell, A.; Stimming, U.; Kortz, U. Inorg. Chem. 2014, 53, 5663-5673. [Read Online]
  • 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-
    Ibrahim, M.; Xiang, Y.; Bassil, B. S.; Lan, Y.; Powell, A. K.; de Oliveira, P.; Keita, B.; Kortz, U. Inorg. Chem. 2013, 52, 8399-8408. [Read Online]
  • A Planar {Mn19(OH)12}26+ Assembly Incorporated in 60-Tungsto-6-Silicate Polyanion
    Bassil, B. S.; Ibrahim, M.; Al-Oweini, R.; Asano, M.; Wang, Z.; van Tol, J.; Dalal, N. S.; Choi, K.-Y.; Ngo Biboum, R.; Keita, B.; Nadjo, L.; Kortz, U. Angew. Chem. Int. Ed. 2011, 50, 5961-5964. [Read Online]
  • Hexadeca-Cobalt(II) Containing Polyoxometalate-Based Single-Molecule Magnet
    Ibrahim, M.; Lan, Y.; Bassil, B. S.; Xiang, Y.; Suchopar, A.; Powell, A. K.; Kortz, U. Angew. Chem. Int. Ed. 2011, 50, 4708-4711. [Read Online]

» Complete List of Publications