Catena-(bis((1,10-phenanthroline-N,N0)-copper(II)) hydroxy-bis (phosphato)-tris(dioxo-vanadium(v))): A polymorphic phase driven by disorder

CRISTIAN SILVA-GALAZ; MARIANELA SALDÍAS; ELEONORA FREIRE; RICARDO BAGGIO; ERIC LE FUR; VERÓNICA PAREDES-GARCIA; EVGENIA SPODINE; DIEGO VENEGAS-YAZIGI

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 1051 p. 205 - 210

0022-2860

In the present paper a copper(II) phosphovanadate is presented and formulated as [Cu6(phen)6(VVO2)6(PO4)6(VVO2HO)3] (1a). This compound was obtained by hydrothermal synthesis and crystallizes in the triclinic group P-1, with a = 10.6290(5), b = 17.4275(8), c = 23.6151(11) Å; a = 92.888(4), b = 98.910(4) and c = 91.995(4). The leitmotif in (1a) is almost identical to some previously reported ones, viz. [Cu(phen)(VVO2)(PO4)]2[VVO2(OH)] (2); [Cu(phen)(VVO2)(PO4)]2[VIVO2(H2O)] (3) except for the fact that the small cellsfound in (2)?(3) are tripled in (1a). The reasons driving to these differences are subtle, and reside in the way in which the disorder in some vanadate groups takes place, viz., completely at random in (2)?(3) thus leading to a small ??average?? cell, while keeping some systematics in (1a) thus needing for a larger motif to take account of its repetition scheme in the crystal. The magnetic unit in the structure of (1a) is defined by a dinuclear system of CuII bonded by a l2,g1-PO4 bridge. A fit of the corresponding magnetic data of (1a) was done, using the van Vleck equation for two S = ½centres ðH ¼ JbS a bS bÞ. The parameters obtained by the fit of the experimental data were g = 2.1 and J = 3.5 cm1.