Publication Date
2018
Department
Ames Laboratory; Materials Science and Engineering
Campus Units
Materials Science and Engineering, Ames Laboratory
Report Number
IS-J 9582
DOI
10.1039/C8TC00322J
Journal Title
Journal of Materials Chemistry C
Volume Number
6
First Page
2862
Last Page
2872
Abstract
A family of isostructural undecanuclear 3d–4f coordination clusters of formula [FeIII7LnIII4O4(OH)3(tea)2(Htea)3(Piv)7(H2O)2(NO3)3], where Ln = Y (1), Gd (2), Tb (3), Dy (4); PivH ≡ pivalic acid and H3tea ≡ triethanolamine, was synthesised. The central Fe7 core of the coordination cluster can be described in terms of two {Fe4O2} butterfly motifs sharing a common body Fe atom. The two Fe4 mean-planes subtend a dihedral angle of ca. 72°. The Tb (3) and Dy (4) compounds show Single Molecule Magnet (SMM) behaviour as confirmed by ac-susceptibility and μ-SQUID measurements. Furthermore, 57Fe Mössbauer spectra of 1–4 confirm the presence of high-spin FeIII sites. The spectra of all complexes in the high temperature range (30–300 K) show broad overlapping doublets which were assigned to the body and wing-tip pairs of metal ions within the Fe7 core. The low temperature Mössbauer spectra show dependence on the nature of the rare-earth metal as a result of its interaction with the iron sites. Thus, we observed a transition from fast (2), to intermediate (1) and very slow (frozen) (3, 4) spin fluctuation phenomena in these compounds.
Language
en
Department of Energy Subject Categories
29 ENERGY PLANNING, POLICY, AND ECONOMY
Publisher
Iowa State University Digital Repository, Ames IA (United States)
