A MnII6MnIII6 Single-Strand Molecular Wheel with a Reuleaux Triangular Topology: Synthesis, Structure, Magnetism, and DFT Studies

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• 作者：Sotiris Zartilas ; Constantina Papatriantafyllopoulou ; Theocharis C. Stamatatos ; Vassilios Nastopoulos ; Eduard Cremades ; Eliseo Ruiz ; George Christou ; Christos Lampropoulos ; Anastasios J. Tasiopoulos
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：October 21, 2013
• 年：2013
• 卷：52
• 期：20
• 页码：12070-12079
• 全文大小：394K
• 年卷期：v.52,no.20(October 21, 2013)
• ISSN：1520-510X

文摘

The use of the anion of 3-methyl-1,3,5-pentanetriol (mpt^{3鈥?/sup>) in manganese carboxylate chemistry has afforded the new MnII/III₁₂ cluster [MnII₆MnIII₆(mpt)₆(CH₃CO₂)₁₂(py)₆]路3CH₃CN (1路3CH₃CN). Complex 1 was isolated in moderate yield by the reaction of Mn(CH₃CO₂)₂路4H₂O and H₃mpt in a 2.6:1 molar ratio in a solvent mixture of acetonitrile and pyridine. The structure of 1 consists of alternating [MnII₂(CH₃CO₂)₃(py)]+ and [MnIII₂(渭-OR)₂(CH₃CO₂)(py)]3+ dimeric units (three of each dimer), linked at each end by two alkoxo and one acetate bridges; the mpt3鈥?/sup> ligands adopt the 畏2:畏2:畏2:渭₄ coordination mode. The overall metal topology of this new Mn₁₂ wheel resembles a guitar plectrum, or a Reuleaux triangle. Complex 1 displays an unprecedented structural topology, being the first example of a MnII₆MnIII₆ wheel constructed from alternating homovalent dimers and the only known Mn₁₂ loop with the trigonal symmetry of a Reuleaux triangle (all other reported loops were ellipsoids). Variable-temperature, solid-state direct- and alternating-current magnetization studies were carried out on complex 1, revealing the presence of antiferromagnetic exchange interactions between the metal ions in the molecule, which lead to a spin ground-state value S = 0; the exchange coupling parameters J were calculated using density functional theory employing a hybrid B3LYP functional.}