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

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 fivecoordinate complexes with coordination of the pendent etherbearing lariat in the solid state. Thermogravimetric analysis showed complexes 2-4 all to have residual masses at 200 degrees 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 degrees 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 degrees C on silicon substrates.