Synthesis, Structure and CVD Studies of 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 form [Me2M{ MeC(O)CHC(NCH2CH2OMe)CF3}] (M = Al (2), Ga (3) or In (4)) have been 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, NMR spectroscopy, and the molecular structures of the complexes were determined by single crystal X-ray diffraction which reveals the compounds to be monomeric 5 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 show the indium complex (4) to be an order of magnitude less volatile (0.09 Torr at 80 oC) than the Al (2) or Ga (3) derivatives despite being isoleptic systems. Complexes 2-4 have all been investigated for their utility in the LP-MOCVD growth of the respective metal oxides in the absence of additional oxidant at 400 °C on silicon substrates.