Artículo de revista
Magnetic properties of phosphate-bridged copper(II) organic-inorganic hybrid compounds
Fecha
2003Registro en:
Journal of Materials Chemistry, Volumen 13, Issue 9, 2003, Pages 2381-2387
09599428
10.1039/b212463g
Autor
Moreno, Yanko
Vega, Andrés
Ushak, Svetlana
Baggio, Ricardo
Peña, Octavio
Le Fur, Eric
Pivan, Jean
Spodine Spiridonova, Evgenia
Institución
Resumen
Hydrothermal synthesis has allowed us to isolate and characterize three new inorganic organic hybrid materials, the compounds [Cu-2(phen)(2)(H2O)(2)(H2PO4)(2)](NO3)(2).2H(2)O (1), [(Cu(2)bipy(2))(2)(V4O9)(PO4)(2)(HPO4)(H2P2O7)](n).nH(2)O (2) and [Cu-2(dpa)(2)(V2P2O12)](n), (4), which have been magneto-structurally characterized. In addition, the magnetic behaviour of the related compound [Cu-2(bipy)(2)(VO2)(2)(PO4)(2)](n) (3), has been measured. Compound 1 has a dimeric structure, while compound 2 and 4 have dimer chain structures. The dependence of the magnetic susceptibility on temperature suggests antiferromagnetic coupling for 1, 2 and 3, while compound 4 can be well understood in terms of the Curie-Weiss law with theta = -23 K. The fitting of the magnetic behaviour to the Bleaney-Bowers spin-dimer coupling expression leads to J = -8.0 cm(-1) for 1, J = -28.8 cm(-1) for 2 and J = -29.0 cm(-1) for 3. The use of alternating chain expressions leads to J = -28.8 cm(-1), alpha = -0.03 for 2 and J = -29.4 cm(-1), alpha = -0.027 for 3. Although a variety of coordination geometries are exhibited by the compounds in the series, all of them have O-P-O bridges connecting the cupric centres. It was possible to identify the role of the vanadyl groups of the phosphovanadate framework as an important factor affecting the ability of the phosphate groups to transmit magnetic interactions.