The combination of multinuclear solid-state NMR spectroscopy and powder X-ray diffraction has been applied to characterize the octahedron-shaped crystalline nanoparticle products resulting from an inverse micelle synthesis. Rietveld refinements of the powder X-ray diffraction data from the nanoparticles revealed their general formula to be (H3O)Y3F_(10)·xH2O. ~1H magic-angle spinning (MAS) NMR experiments provided information on sample purity and served as an excellent probe of the zeohthic incorporation of atmospheric water, ~(19)F MAS NMR experiments on a series of monodisperse nanoparticle samples of various sizes yielded spectra featuring three unique ~(19)F resonances arising from three different fluorine sites within the (H3O)Y3F_(10)·xH2O crystal structure. Partial removal of zeolithic water from the internal cavities and tunnels of the nanoparticles led to changes in the integrated peak intensities in the ~(19)F MAS NMR spectra; the origin of this behavior is discussed in terms of ~(19)F longitudinal relaxation. ~(19)F-~(89)Y variable-amplitude cross-polarization (VACP) NMR experiments on both stationary samples and samples under MAS conditions indicated that two disrinct yttrium environments are present, and on the basis of the relative peak intensities, the population of one of the two sites is closely linked to the nanoparticle size. Both ~(19)F MAS and ~(19)F-~(89)Y VACP/MAS expenments mdicated small amounts of an impurity present in certain nanoparticles; these are postulated to be spherical amorphous YF3 nanopartides. We discuss the importance of probing molecular-level structure in addition to microscopic structure and how the combination of these characterization methods is crucial for understanding nanoparticle design, synthesis, and application.
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机译：多核固态NMR光谱和粉末X射线衍射的结合已应用于表征由反胶束合成产生的八面体形晶体纳米颗粒产物。来自纳米颗粒的粉末X射线衍射数据的Rietveld精炼显示它们的通式为（H 3 O）Y 3 F_（10）·xH 2O。 〜1H魔角旋转（MAS）NMR实验提供了样品纯度的信息，并且是大气水的沸石结合的极好探针，〜（19）F MAS NMR实验是对一系列各种尺寸的单分散纳米颗粒样品进行的光谱分析具有（H3O）Y3F_（10）·xH2O晶体结构中三个不同氟位点引起的三个独特的〜（19）F共振。从纳米粒子的内腔和隧道中部分除去沸石水导致〜（19）F MAS NMR光谱中积分峰强度的变化;这种行为的起源是根据〜（19）F纵向弛豫来讨论的。在固定样品和MAS条件下对样品进行的〜（19）F-〜（89）Y变幅交叉极化（VACP）NMR实验表明，存在两个离散钇环境，并基于相对峰强度，两个位点之一的人口与纳米颗粒大小密切相关。 〜（19）F MAS和〜（19）F-〜（89）Y VACP / MAS费用都表明某些纳米颗粒中存在少量的杂质。这些被假定为球形无定形的YF 3纳米粒子。除了微观结构，我们还将探讨探测分子级结构的重要性，以及这些表征方法的组合对于理解纳米颗粒的设计，合成和应用至关重要。
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