Neutron Diffraction and Theoretical DFT Studies of Two Dimensional Molecular-Based Magnet K2[Mn(H2O)2]3[Mo(CN)7]2·6H2O

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• 作者：B&eacute ; atrice Gillon ; Antoine Goujon ; St&eacute ; phanie Willemin ; Joulia Larionova ; C&eacute ; dric Desplanches ; Eliseo Ruiz ; Gilles Andr&eacute ; John A. Stride ; Christian Gu&eacute ; rin
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：February 19, 2007
• 年：2007
• 卷：46
• 期：4
• 页码：1090 - 1099
• 全文大小：360K
• 年卷期：v.46,no.4(February 19, 2007)
• ISSN：1520-510X

文摘

Exchange mechanisms and magnetic structure in the two-dimensional cyano-bridged molecule-based magnet K₂[Mn(H₂O)₂]₃[Mo(CN)₇]₂·6H₂O have been investigated by a combination of neutron diffraction studies on both singlecrystal and powder samples and theoretical DFT calculations. The experimental spin density has been deducedfrom a new refinement of previously obtained polarized neutron diffraction (PND) data which was collected in theordered magnetic state at 4 K under a saturation field of 3 T performed in the C2/c space group, determined byan accurate re-evaluation of the X-ray structure. Positive spin populations were observed on the two manganesesites, and negative spin populations were observed on the molybdenum site, which provides evidence ofantiferromagnetic Mo³⁺-Mn²⁺ exchange interactions through the cyano bridge. The experimental data have beencompared to the results of DFT calculations. Moreover, theoretical studies reveal the predominance of the spinpolarization mechanism in the Mo-C-N-Mn sequence, with the antiferromagnetic nature of the interaction beingdue to the overlap between the magnetic orbitals relative to manganese and molybdenum in the cyano bridgingregion. The magnetic structure of K₂[Mn(H₂O)₂]₃[Mo(CN)₇]₂·6H₂O has been solved at low temperature in zero fieldby powder neutron diffraction measurements. The structure was found to be ferrimagnetic where the manganeseand molybdenum spins are aligned along the ages/entities/bvector.gif"> axis in opposite directions.