Heterometallic Fe^III-Ce^IV complexes from the use of aliphatic aminoalcohol ligands

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• 作者：Christos M. Kizas ; Constantina Papatriantafyllopoulou ; Manolis J. Manos ; Anastasios J. Tasiopoulos ; ^{atasio@ucy.ac.cy}
• 关键词：Iron(III) clusters ; Cerium(IV) clusters ; 3d&ndash ; 4f Clusters ; Aliphatic aminoalcohols ; Crystal structures ; Magnetic properties
• 刊名：Polyhedron
• 出版年：2013
• 出版时间：22 March, 2013
• 年：2013
• 卷：52
• 期：Complete
• 页码：346-354
• 全文大小：698 K

文摘

Six novel heteronuclear Fe^III/Ce^IV clusters with the ligands 3-amino-1-propanol (Hap) and 2-(hydroxymethyl)piperidine (Hhmpip) [Fe^III₄Ce^IV₆O₈(L)₄((CH₃)₃CCO₂)₁₂(RCO₂)₄] (R = CH₃, L = ap^?, 1; R = ClCH₂, L = ap^?, 2; R = BrCH₂, L = ap^?, 3; R = C₂H₅, L = ap^?, 4; R = CH₃, L = hmpip^?, 5) and ([Fe₂Ce₂Na₂O₂((CH₃)₃CCO₂)₈(N₃)₂(ap)₂])_¡Þ (6)_¡Þ are reported. Compounds 1-5 were prepared from reactions of preformed trinuclear Fe³⁺ clusters with the ligands, in the presence of (NH₄)₂Ce(NO₃)₆ and RCO₂M (R = CH₃, M⁺ = H⁺, 1; R = ClCH₂, M⁺ = Na⁺, 2; R = BrCH₂, M⁺ = Na⁺, 3; R = CH₃CH₂, M⁺ = Na⁺, 4; R = CH₃, M⁺ = H⁺, 5) in 1:5:1:1 molar ratio in CH₃CN. Complex (6¡¤2CH₃CN)_¡Þ was prepared by a similar to the above described synthetic procedure that involved the use of NaN₃ instead of RCO₂M. To the best of our knowledge, compounds 1-6 are the initial examples of Fe^III/Ce^IV species and rare examples of metal complexes with the ligands Hap and Hhmpip. The structures of 1-5 are composed of a distorted supertetrahedral [Fe^III₄Ce^IV₆(¦Ì₄-O)₄(¦Ì₃-O)₄]²⁰⁺ structural core, while (6¡¤2CH₃CN)_¡Þ displays a [Fe^III₂Ce^IV₂Na₂(¦Ì₄-O)₂]¹²⁺ core consisting of two tetrahedral units sharing one common edge. These two structural types are rather uncommon for mixed metal 3d/4f compounds although they are well-known for 3d metal cluster chemistry. Variable temperature dc magnetic susceptibility studies on powdered microcrystalline samples of 1 and (6¡¤2CH₃CN)_¡Þ revealed the presence of weak antiferromagnetic interactions as expected on the basis of the large separations (>6 ?) between the paramagnetic Fe³⁺ ions in both complexes.