Multinuclear magic-angle spinning and double-rotation NMR study of the synthesis and assembly of a sodalite semiconductor supralattice

Abstract

{sup 29} Si-magic-angle spinning, {sup 27}Al and {sup 23}Na magic-angle spinning, and double rotation NMR provide structural and electronic details for the newly developed sodalite semiconductor quantum supralattices. The evolution of the nucleation and crystallization processes of sodium halide sodalites is monitored, and the appearance of anion-empty sodalite cages is detected. Subtle changes in the electronic and quadrupole interactions of sodium and aluminum nuclei occur upon loading chloride, bromide, and iodide into the sodalite cages. The NMR results suggest that the development of electronic coupling occurs throughout the lattice in mixed-halide chloro,iodosodalites. A preference for silver exchange of sodium cations in halide-containing cages, over hydroxide-containing and anion-empty sodalite cavities, is detected. Extraction of the isotropic chemical shift and quadrupole contributions to the sodium resonances is achieved by performing the NMR experiments at two magnetic field strengths. The parameters obtained indicate a change in the charge distribution around the sodium nuclei upon exchanging approximately one-quarter of the extraframework Na{sup +} cations with silver, which parallels other data pointing to the onset of a semiconductor supralattice within the sodalite matrix. 30 refs., 15 figs., 3 tabs.