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The Metastable, Glasslike Solid‐State Phase of HAlO and Its Transformation to Al/Al 2 O 3 Using a CO 2 Laser
Author(s) -
Veith Michael,
Andres Kathrin,
Blin Joel,
Zimmer Michael,
Wolf Yan,
Schnöckel Hansgeorg,
Köppe Ralf,
de Masi Remo,
Hüfner Stefan
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200300485
Subject(s) - chemistry , x ray photoelectron spectroscopy , hydrogen , analytical chemistry (journal) , amorphous solid , spectroscopy , infrared spectroscopy , stoichiometry , metastability , crystallography , nuclear magnetic resonance , organic chemistry , physics , quantum mechanics
Bis( tert ‐butoxyaluminum dihydride) ( t BuOAlH 2 ) 2 decomposes on metal surfaces heated to 250 °C (Fe, Ni, Cu, Pt) and under reduced pressures of 0.01−0.1 atm with elimination of dihydrogen and isobutene to form a glasslike, amorphous film, which is composed of equimolar parts of hydrogen, aluminum and oxygen (elemental analysis, EDX analysis). The gases eliminated during this process were characterized by mass spectroscopy (H 2 , isobutene) or by infrared matrix techniques (isobutene). The exclusive binding of hydrogen to aluminum is deduced from IR spectroscopy of the HAlO film and of its deuterated form DAlO. The HAlO layer (which shows no X‐ray diffraction pattern), when heated to 450 °C or when exposed to a CO 2 laser, loses hydrogen and transforms to an almost stoichiometric composite with nanoscale crystalline aluminum and aluminum oxide (Al/Al 2 O 3 ) as ingredients. This transformation may be followed by IR spectroscopy, by 27 Al MAS NMR or by XPS, the latter showing different signals (Al, 2p electrons, Mg‐ K α , θ = 0°) for HAlO (74.2 eV) and for the composite (Al: 72.1 eV, Al 2 O 3 : 75.3 eV). Microstructures that are characterized by different chemical compositions and different optical contrasts of the “drawing”, relative to the surrounding matrix, may be generated with an X/Y‐table and a CO 2 laser. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)