Neutral and Cationic Methylaluminium Complexes of 2‐Anilinotropone Ligands: Synthesis, Characterization, and Reactivity toward Ethylene

Some new aluminium complexes bearing bidentate monoanionic 2‐anilinotroponate ligands have been synthesized and characterized. Reaction of 2‐(2,6‐diisopropylanilino)tropone or 2‐(perfluoroanilino)tropone with AlMe 3 (1 equiv.) gave, by methane elimination, compounds [2‐(2,6‐diisopropylanilino)tropone]AlMe 2 ( 1 ) and [2‐(perfluoroanilino)tropone]AlMe 2 ( 2 ), respectively, as yellow solids. Reaction of 1 with 1 equiv. of the ligand furnished, by protodealumination of a second Al−CH 3 bond, the [2‐(2,6‐diisopropylanilino)tropone] 2 AlMe derivative 3 . The structure of 3 has been determined by single‐crystal X‐ray diffraction, showing a five‐coordinate aluminium atom with a distorted trigonal‐bipyramidal geometry. Compounds 1 and 3 underwent methyl abstraction reactions with B(C 6 F 5 ) 3 ; the resulting cationic species was trapped in the presence of THF in dichloromethane solution. The reactivity of the synthesized compounds in ethylene polymerisation has also been explored. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)