Effect of Ligand Substitution on the Exchange Interactions in {Mn12}-Type Single-Molecule Magnets

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• 作者：Danil W. Boukhvalov ; Viatcheslav V. Dobrovitski ; Paul Kgerler ; Mohammad Al-Saqer ; Mikhail I. Katsnelson ; Alexander I. Lichtenstein ; Bruce N. Harmon
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：December 6, 2010
• 年：2010
• 卷：49
• 期：23
• 页码：10902-10906
• 全文大小：799K
• 年卷期：v.49,no.23(December 6, 2010)
• ISSN：1520-510X

文摘

We investigate how ligand substitution affects the intramolecular spin exchange interactions, studying a prototypical family of single-molecule magnets comprising dodecanuclear cluster molecules [Mn^III₈Mn^IV₄O₁₂(COOR)₁₆]. We identify a simple scheme based on accumulated Pauling electronegativity numbers (AEN) of the carboxylate ligand groups (R). The redistribution of the electron density, controlled by the AEN of a ligand, changes the degree of hybridization between 3d electrons of manganese and 2p electrons of oxygen atoms, thus changing the exchange interactions. This scheme, despite its conceptual simplicity, provides a strong correlation with the exchange energies associated with carboxylate bridges and is confirmed by the electronic structure calculations taking into account the Coulomb correlations in magnetic molecules.