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 71Ga NMR of hydroxo-aquo metal clusters and the impurities present.
• High-field NMR capability allows for quadrupolar species, such as 71Ga, to be routinely studied.
• Efficient and environmentally friendly synthetic routes have been developed to prepare hydroxo-aquo metal clusters.

Solid-state 71Ga NMR was used to characterize a series of [Ga13(μ3-OH)6(μ2-OH)18(H2O)](NO3)15 “Ga13” 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 Ga13 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 71Ga.

The various synthetic routes and 71Ga solid-state NMR spectra of the nanoscale inorganic cluster [Ga13(μ3-OH)6(μ2-OH)18(H2O)](NO3)15. Figure optionsDownload as PowerPoint slide