Synthesis, Structure and Chemical Vapour Deposition Studies on the Group 13 Complexes [Me2M­{tfacnac}] [M = Al, Ga, In; Htfacnac = F3CC(OH)CHC(CH3)NCH2CH2OCH3]

• Published in: European journal of inorganic chemistry 2016-04, Vol.2016 (11), p.1712-1719
• Main Authors: Cosham, Samuel D., Hamilton, Jeff A., Hill, Michael S., Johnson, Andrew L., Molloy, Kieran C.
• Format: Article
• Language: English
• Subjects: Aluminum; Chemical vapor deposition; Coordination compounds; Gallium; Indium; Metal oxides; Oxidants; Thin films; Tridentate ligands; Vapor pressure
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201600023

A family of group 13 metal dimethyl complexes of the general formula [Me2M{MeC(O)CHC(NCH2CH2OMe)CF3}] [M = Al (2), Ga (3) or In (4)] was synthesised by reaction of the isolated free ligand 1 with the corresponding trimethyl metal reagents. The isolated complexes 2–4 were characterised by elemental analysis and NMR spectroscopy, and the molecular structures of the complexes were determined by single‐crystal X‐ray diffraction, which revealed them to be monomeric five‐coordinate complexes with coordination of the pendent ether‐bearing lariat in the solid state. Thermogravimetric analysis showed complexes 2–4 all to have residual masses at 200 °C of 2.4 % or less, well below the value for the respective metal oxides, and vapour pressure measurements showed the indium complex 4 to be an order of magnitude less volatile (0.09 Torr at 80 °C) than the Al (2) and Ga (3) analogues, despite their being isoleptic systems. Complexes 2–4 were investigated for their utility in the low‐pressure metal organic chemical vapour deposition of the respective metal oxides in the absence of additional oxidant at 400 °C on silicon substrates. Complexes [Me2M{MeC(O)CHC(NCH2CH2OMe)CF3}] (M = Al, Ga, In) were synthesised and evaluated for their application in the CVD of metal oxide thin films. Although the In complex is an order of magnitude less volatile than the Al and Ga analogues, CVD of the In precursor in the absence of additional O2 oxidant produced highly orientated thin films of (222)‐oriented In2O3.