The synthesis, structural characterization, magnetochemistry and Mössbauer spectroscopy of [Fe3LnO2(CCl3COO)8H2O(THF)3] (Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Lu and Y) Article - 2009

Valeriu Mereacre, Denis Prodius, Constantin Turta, Sergiu Shova, George Filoti, Juan Bartolomé, Rodolphe Clérac, Christopher E. Anson, Annie K. Powell

Valeriu Mereacre, Denis Prodius, Constantin Turta, Sergiu Shova, George Filoti, Juan Bartolomé, Rodolphe Clérac, Christopher E. Anson, Annie K. Powell, « The synthesis, structural characterization, magnetochemistry and Mössbauer spectroscopy of [Fe3LnO2(CCl3COO)8H2O(THF)3] (Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Lu and Y)  », Polyhedron, 2009, pp. 3017-3025. ISSN 0277-5387

Abstract

The new tetranuclear complexes [Fe3Ln(l3-O)2(CCl3COO)8(H2O)(THF)3]THF (Ln = CeIII (1), PrIII (2), NdIII(3)) and [Fe3Ln(l3-O)2(CCl3COO)8(H2O)(THF)3]THFC7H16 (Ln = SmIII (4), EuIII (5), GdIII (6), TbIII (7), DyIII (8), HoIII (9), LuIII (10) and YIII (11)) have been prepared. All compounds were prepared by the reaction between [Fe2BaO(CCl3COO)6(THF)6] and the corresponding LnIII nitrate salt. The crystal structures of 1–4, 8 and 9 have been determined ; these isostructural molecules have a non-planar Fe3Ln(l3-O)2 ‘‘butterfly” core. Magnetic susceptibility measurements show dominant intramolecular antiferromagnetic exchange interactions for all the complexes. 57Fe Mössbauer spectroscopy shows three different environments for the FeIII metal ions, all in their high-spin state S = 5/2 (confirming that no electron transfer from CeIII to FeIII occurs in 1). At the time scale of the Mössbauer spectroscopy (about 107 s), evidence of magnetization blocking, i.e. slow relaxation of the magnetization, is observed below 3 K for 7, which was confirmed by ac susceptibility measurements.

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