Low-Coordinate Mixed Ligand NacNac Complexes of Rare Earth Metals.

We report the synthesis and characterization of two types of new mixed-ligand rare earth complexes: tetracoordinate (NacNac Mes )Ln(BIAN dipp ) (Ln = Dy ( 1 ), Er ( 2 ) and Y ( 3 )) and pentacoordinate (NacNac Mes )Ln(AP dipp )(THF) (Ln = Dy ( 4 ), Er ( 5 ) and Y ( 6 )). The first three compounds were prepared by the reaction of [(BIAN Dipp )LnI] with potassium β-diketiminate. The salt metathesis of β-diketiminato-supported rare earth dichlorides (NacNac Mes )LnCl 2 (THF) 2 with sodium o-amidophenolate results in compounds 4 - 6 . The crystal structures of complexes 1 - 6 were determined by single-crystal analysis. The combination of bulky monoanionic N-mesityl-substituted β-diketiminates with sterically hindered redox-active ligands led to the very low coordination numbers of rare earths and strong distortion of the chelate ligands.