95Mo Solid-State Nuclear Magnetic Resonance Spectroscopy and Quantum Simulations: Synergetic Tools for the Study of Molybdenum Cluster Materials

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• 作者：J茅r么me Cuny ; St茅phane Cordier ; Christiane Perrin ; Chris J. Pickard ; Laurent Delevoye ; Julien Tr茅bosc ; Zhehong Gan ; Laurent Le Poll猫s ; R茅gis Gautier
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：January 18, 2013
• 年：2013
• 卷：52
• 期：2
• 页码：617-627
• 全文大小：607K
• 年卷期：v.52,no.2(January 18, 2013)
• ISSN：1520-510X

文摘

The ability of ⁹⁵Mo solid-state nuclear magnetic resonance (SSNMR) spectroscopy to probe the atomic and electronic structures of inorganic molybdenum cluster materials has been demonstrated for the first time. Six cluster compounds were studied: MoBr₂, Cs₂Mo₆Br₁₄, (Bu₄N)₂Mo₆Br₁₄, each containing the octahedral Mo₆Br₁₄^{2鈥?/sup> cluster unit, and MoS₂Cl₃, Mo₃S₇Cl₄, and MoSCl that contain metallic dimers, trimers, and tetramers, respectively. To overcome inherent difficulties due to the low sensitivity of 95Mo SSNMR, both high-magnetic-field spectrometers and the quadrupolar Carr鈥揚urcell Meiboom鈥揋ill sensitivity enhancement pulse sequence under magic-angle-spinning conditions, combined with a hyperbolic-secant pulse were used. Experimental measurements as well as characterization of the 95Mo electric field gradient and chemical shift tensors have been performed with the help of quantum-chemical calculations under periodic boundary conditions using the projector augmented-wave and the gauge-including projector augmented-wave methods, respectively. A large 95Mo chemical shift range is measured, 3150 ppm, and the isotropic chemical shift of the Mo atoms is clearly correlated to their formal oxidation degree in the various clusters. Furthermore, a direct relation is evidenced between the molybdenum quadrupolar coupling constant and the bond lengths with its surrounding ligands. Our results demonstrate the efficiency of the combined use of quantum-chemical calculations and 95Mo SSNMR experiments to study inorganic molybdenum cluster compounds.}