A single-source CVD precursor to MgAl2O4: [Mg{((OBu)-Bu-t)(2)AlH2}(2)]

The hydride-modified heterometal alkoxide [Mg((O'Bu)(2)AlH2](2) ] (1), a pr ecursor with tailored composition for single-source chemical vapor depositi on (CVD) synthesis of MgA1(2)O, has been synthesized and characterized usin g spectroscopic methods and single-crystal X-ray diffraction analysis. Ther mal decomposition of 1, in a CVD process, on an inductively heated (450 deg rees C) metal substrate (steel, Ni, Cu) gave crystalline deposits of high p urity MgAl2O4 with low carbon contamination (<0.5 %) and nano-sized crystal lites (<10 nm). Analysis of the pyrolysis gases using on-line mass spectros copy, and comparing the results obtained with the deuterated compound [Mg(( O'Bu)(2)AlD2]2 (2), confirmed the gaseous products to be isobutylene (2-met hylpropene) and dihydrogen (HD in the case of 2). The (27)A1 magic angle sp inning (MAS) NMR study of the obtained spinel shows a partly inverse struct ure with Al3+ ions occupying both octahedral and tetrahedral sites. This di stribution (octahedral/tetrahedral) remains unaltered even on heat treatmen t. The thin layers obtained were characterized using glow discharge mass sp ectrometry (GDMS), energy dispersive X-ray (EDX), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), solid-state NMR and C-H analysis.