Synthesis and structure of four-coordinate dimethyl aluminium complexes incorporating new N,O-chelating arylamido ligands

A new type of arylamido ligands with an intramolecular coordinating ortho-ether-substituent (i.e. a O,N− chelating ligand) is introduced. The achiral and chiral 4-coordinate dimethyl aluminium complexes [2-ROC6H4NR′]AlMe2 (4a: R=R′=Cy; 4b: R=(−)-menthyl, R′=Cy, 4c: R=(−)-menthyl, R′=CPh3) have been prepared by reaction of the appropriate amido Li salt with ClAlMe2. Complex 4a could also be obtained, via methane elimination, by reaction of AlMe3 with the corresponding ligand. The presence of two rotamers in solution at room temperature for 4b and for 4c is most likely due to a restricted rotation of the (−)-menthyl group at this temperature due to severe steric interactions with the rest of the complex.