High nuclearity cerium-manganese clusters and their structural and magnetic properties: Ce^IV₃Mn^III₇ and Ce^IV₅Mn^III₁₁

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• 作者：Annaliese E. Thuijs ; Andrea Marton ; Theocharis C. Stamatatos¹ ; Khalil A. Abboud ; George Christou ; ^{christou@chem.ufl.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Manganese ; Lanthanide ; Single-molecule magnet ; Crystal structures ; Cerium
• 刊名：Polyhedron
• 出版年：2016
• 出版时间：8 January 2016
• 年：2016
• 卷：103
• 期：part_PB
• 页码：288-294
• 全文大小：1132 K

文摘

The syntheses, structures, and magnetic properties are reported of two new high nuclearity Ce–Mn oxo carboxylate clusters at high Ce^IV/Mn^III oxidation states and with nuclearities of Ce₅Mn₁₁ and Ce₃Mn₇. The compounds are (NⁿBu₄)₂[Ce₅Mn₁₁O₁₃(OH)₂(O₂CPh)₂₄(NO₃)₂](NO₃) (1) and [Ce₃Mn₇O₈(O₂CPh)₁₇(H₂O)₄] (2). 1 was prepared from the oxidation of Mn(O₂CPh)₂ by (NⁿBu₄)₂Ce(NO₃)₆, whereas 2 was obtained from the comproportionation reaction of Mn(O₂CPh)₂ and NⁿBu₄MnO₄ in the presence of Ce(NO₃)₃. Both compounds possess unprecedented structures, comprising an irregular metal topology of several edge-fused triangular units with overall virtual C₂ symmetry. Variable-temperature, solid-state dc and ac magnetization studies on 1 and 2 in the 1.8–300 K range revealed predominantly weak antiferromagnetic exchange interactions within the complexes. For 1, the combined dc and ac data indicate an S = 5 ground state but with low-lying excited states consistent with the high nuclearity. For 2, even lower-lying excited states were observed, precluding clear determination of the ground state but with an estimate of S = 2 or 3, or less. Complexes 1 and 2 are new additions to the Ce–Mn family of clusters and the broader class of 3d/4f molecular systems, and 1 is the highest nuclearity Ce–Mn cluster to date.