87Sr, 119Sn, 127I Single and {1H/19F}-Double Resonance Solid-State NMR Experiments: Application to Inorganic Materials and Nanobuilding Blocks
Résumé
87Sr, 127I and 119Sn wideline NMR spectroscopy was successfully applied to inorganic and hybrid materials: (i) Sr derivatives of medicinal interest (Sr-malonate, Sr-pyrophosphates, mixed Ca,Sr-fluoroapatites); (ii) apatitic structures acting as host matrices for iodine; and (iii) Sn-derived oxo-clusters which can be used as inorganic nanobuilding blocks. The BRAIN (BRoadband Adiabatic INversion) CP (Cross Polarization) approach (by Schurko et al.) was applied to a non integer quadrupolar nucleus (87Sr, I=9/2). The sequence was used in combination with WURST (Wideband Uniform-Rate Smooth-Truncation) QCPMG (Quadrupolar Carr-Purcell Meiboom-Gill) for optimal sensitivity. We showed that 127I WURST QCPMG experiments were sufficiently sensitive to allow rapid characterization of the incorporation of iodide (I−) anions in lead vanadate/phosphate apatites, and that 127I acted as a sensitive probe for the description of local disorder. 1H/19F → 119Sn BRAIN CP was successfully applied to the detailed characterization of tin oxo-clusters, using 1H and 19F as spin baths. We demonstrated that BRAIN CP can be effectively used as a tool of spectral editing leading to the estimation of spatial proximities between 119Sn and 1H/19F nuclei.