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Science 21 April 1995:
Vol. 268. no. 5209, pp. 397 - 400
DOI: 10.1126/science.268.5209.397
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Articles

High-Temperature Molecular Magnets Based on Cyanovanadate Building Blocks: Spontaneous Magnetization at 230 K

William R. Entley 1 and Gregory S. Girolami 1

1 School of Chemical Sciences and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 505 South Mathews Avenue, Urbana, IL 61801, USA.

The molecular-based magnetic materials Cs2Mn||[V||(CN)6] (1) and (Et4N)0.5Mnl.25- [V(CN)5]·2H2O (2) (where Et is ethyl) were prepared by the addition of manganese(II) triflate to aqueous solutions of the hexacyanovanadate(II) ion at 0°C. Whereas 1 crystallizes in a face-centered cubic lattice, 2 crystallizes in a noncubic space group. The cesium salt (1) has features characteristic of a three-dimensional ferrimagnet with a Néel transition at 125 kelvin. The tetraethylammonium salt (2) also behaves as a three-dimensional ferrimagnet with a Néel temperature of 230 kelvin; only two other molecular magnets have higher magnetic ordering temperatures. Saturation magnetization measurements indicate that in both compounds the VII and high-spin MnII centers are antiferromagnetically coupled. Both 1 and 2 exhibit hysteresis loops characteristic of soft magnets below their magnetic phase-transition temperatures. The high magnetic ordering temperatures of these cyano-bridged solids confirm that the incorporation of early transition elements into the lattice promotes stronger magnetic coupling by enhancing the backbonding into the cyanide pgr* orbitals.

Submitted on October 4, 1994
Accepted on December 30, 1994


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Mixed valency and magnetism in cyanometallates and Prussian blue analogues.
J.M Herrera, A Bachschmidt, F Villain, A Bleuzen, V Marvaud, W Wernsdorfer, and M Verdaguer (2008)
Phil Trans R Soc A 366, 127-138
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Supramolecular Chemistry And Self-assembly Special Feature: Systematic assembly of the double molecular boxes: {Cssubset [CpCo(CN)3]4[Cp*Ru]3} as a tridentate ligand.
S. M. Contakes, M. L. Kuhlman, M. Ramesh, S. R. Wilson, and T. B. Rauchfuss (2002)
PNAS 99, 4889-4893
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