Covalently Linked Dimer of Mn3 Single-Molecule Magnets and Retention of Its Structure and Quantum Properties in Solution

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• 作者：Tu N. Nguyen ; Muhandis Shiddiq ; Tuhin Ghosh ; Khalil A. Abboud ; Stephen Hill ; George Christou
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：June 10, 2015
• 年：2015
• 卷：137
• 期：22
• 页码：7160-7168
• 全文大小：548K
• ISSN：1520-5126

文摘

[Mn₃O(O₂CMe)₃(dpd)_3/2)]₂(I₃)₂ has been obtained from the reaction of 1,3-di(pyridin-2-yl)propane-1,3-dione dioxime (dpdH₂) with triangular [Mn^III₃O(O₂CMe)(py)₃](ClO₄). It comprises two [Mn^III₃O]⁷⁺ triangular units linked covalently by three dioximate ligands into a [Mn₃]₂ dimer. Solid state dc and ac magnetic susceptibility measurements reveal that each Mn₃ subunit of the dimer is a separate single-molecule magnet (SMM) with an S = 6 ground state and that the two SMM units are very weakly ferromagnetically exchange coupled. High-frequency EPR spectroscopy on a single crystal displays signal splittings indicative of quantum superposition/entanglement of the two SMMs, and parallel studies on MeCN/toluene (1:1) frozen solutions reveal the same spectral features. The dimer thus retains its structure and inter-Mn₃ coupling upon dissolution. This work establishes that covalently linked molecular oligomers of exchange-coupled SMMs can be prepared that retain their oligomeric nature and attendant inter-SMM quantum mechanical coupling in solution, providing a second phase for their study and demonstrating the feasibility of using solution methods for their deposition on surfaces and related substrates for study.