title: 95Mo solid-state nuclear magnetic resonance spectroscopy and quantum simulations: synergetic tools for the study of molybdenum cluster materials.
abstract: The ability of (95)Mo 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: MoBr(2), Cs(2)Mo(6)Br(14), (Bu(4)N)(2)Mo(6)Br(14), each containing the octahedral Mo(6)Br(14)(2-) cluster unit, and MoS(2)Cl(3), Mo(3)S(7)Cl(4), and MoSCl that contain metallic dimers, trimers, and tetramers, respectively. To overcome inherent difficulties due to the low sensitivity of (95)Mo SSNMR, both high-magnetic-field spectrometers and the quadrupolar Carr-Purcell Meiboom-Gill 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 (95)Mo 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 (95)Mo 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 (95)Mo SSNMR experiments to study inorganic molybdenum cluster compounds.
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS-Université de Rennes 1-Ecole Nationale Supérieure de Chimie de Rennes, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France. cuny.jerome@phys.chem.ethz.ch
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cuny
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cordier
authors.forename: Christiane
authors.initials: C
authors.lastname: Perrin
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pickard
authors.forename: Laurent
authors.initials: L
authors.lastname: Delevoye
authors.forename: Julien
authors.initials: J
authors.lastname: Trébosc
authors.forename: Zhehong
authors.initials: Z
authors.lastname: Gan
authors.forename: Laurent
authors.initials: L
authors.lastname: Le Pollès
authors.forename: Régis
authors.initials: R
authors.lastname: Gautier