Stepwise conversion of a single source precursor into crystalline AlN by transamination reaction

Ammonolysis of the monomeric, base-stabilized trisaminoalane Me3N-Al[N(H)Dipp)]3 (Dipp=2,6-iPr2–C6H3) yielded Al–N oligomers, which were characterized in detail by solid state NMR spectroscopy (1H, 13C, 15N, 27Al) and TGA/DTA. Pyrolysis of as-prepared oligomers at different temperatures in an argon steam yielded carbon-containing black solids, whereas pyrolysis under a steady flow of NH3 produced pure aluminum nitride (AlN). The role of the pyrolysis temperature and the influence of NH3 on the formation of crystalline materials were investigated. As-prepared AlN was characterized by solid state NMR spectroscopy (15N, 27Al), X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Theoretical calculations were performed in order to identify potential reaction intermediates.