Solid-state NMR characterization of 69Ga and 71Ga in crystalline solids.
Gallium model systems containing four- and six-coordinate gallium sites have been investigated using solid-state NMR. Measurement of the isotropic chemical shift and electric field gradient (EFG) have been performed at 9.4 T on alpha-Ga2O3, beta-Ga2O3, LiGaO2, NaGaO2, KGaO2, Ga2(SO4)3, and LaGaO3 using a variety of techniques on both NMR active nuclei (69Ga and 71Ga) including static, high speed magic-angle spinning (MAS), satellite transition (ST) spectroscopy, and rotor-assisted population transfer (RAPT). The chemical shift is found to correlate well with the coordination number, with four-coordinate gallium having values of approximately 50 ppm and six-coordinate gallium having values near 225 ppm (referenced to 1 M gallium nitrate solution). The magnitude of the EFG is found to be correlated to the distortion of the gallium polyhedra, with the strained systems having EFGs of 3 x 10(21) Vm(-2) or more, while the less strained systems have values of 1.5 x 10(21) Vm(-2) or less. A plot of chemical shift versus EFG suggests that solid-state NMR of gallium oxyanions can be more discriminating than liquid state NMR chemical shifts alone.
Ash
Jason T
JT
Department of Chemistry, Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210-1173, USA.
Grandinetti
Philip J
PJ
D000838:Anions / Q000737:chemistry; D003460:Crystallization; D004560:Electricity; D005707:Gallic Acid / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D005709:Gallium Isotopes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008672:Metals, Alkali / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*
D000838:Anions; D005709:Gallium Isotopes; D008672:Metals, Alkali; D010087:Oxides; D005707:Gallic Acid; D005708:Gallium