Solid-State 69Ga and 71Ga NMR Study of the Nanoscale Inorganic Cluster [Ga13(μ3-OH)6(μ2-OH)18(H2O)24](NO3)15

Solid-state Ga-71 and Ga-69 NMR was used to probe the structure of the hydroxo-aquo cluster, [GA(13)(mu(3)-OH)(6)(mu(2)-OH)(18)(H2O)(24)](NO3)(15), envisioned as a solution-processable material for thin film electronics. This species, termed Ga-13, is made up of three types of 6-coordinate gallium sites, with bridging OH groups and H2O species decorating the outer edges. Solid-state NMR at two magnetic fields (13.9 and 21.1 T) of these quadrupolar nuclei, in conjunction with modeling, demonstrates that these sites are best represented as distorted octahedra, exhibiting a wide range of distinct quadrupolar couplings and asymmetry parameters. This information is critical for analyses of the local coordination environment for gallium in related gallium-oxide films, and this work adds to the growing body of evidence that gallium solid-state NMR is a useful tool for structural analyses.