Synthetic routes to a nanoscale inorganic cluster [Ga13(μ3-OH)6 (μ2-OH)18(H2O)](NO3)15 evaluated by solid-state 71Ga NMR

Solid-state Ga-71 NMR was used to characterize a series of [Ga-13(mu(3)-OH)(6)(mu(2)-OH)(18)(H2O)](NO3)(15) "Ga-13" molecular clusters synthesized by multiple methods. These molecular clusters are precursors to thin film electronics and may be employed in energy applications. The synthetic routes provide varying levels of impurities in the solid phase, and these impurities often elude traditional characterization techniques such as powder X-ray diffraction and Raman spectroscopy. Solid-state NMR can provide a window into the gallium species even in amorphous phases. This information is vital in order to prevent the impurities from causing defect sites in the corresponding thin films upon gelation and condensation (polymerization) of the Ga-13 clusters. This work demonstrates the resolving power of solid-state NMR to evaluate structure and synthetic quality in the solid state, and the application of high-field NMR to study quadrupolar species, such as Ga-71. (C) 2016 Elsevier Inc. All rights reserved.