Dialkylaluminum Complexes with Chelating Anilido-Imine Ligands:  Synthesis, Structures, and Luminescent Properties

Syntheses of three new chelating anilido-imine conjugated ligands, ortho -C 6 H 4 (NHAr‘)(CH NAr‘ ‘) [Ar‘ = Ar‘ ‘ = 2,6-Me 2 C 6 H 3 ( 2b ); Ar‘ = p -MeC 6 H 4, Ar‘ ‘ = 2,6- i Pr 2 C 6 H 3 ( 2c ); Ar‘ = Ar‘ ‘ = p -MeC 6 H 4 ( 2d )], as well as their four-coordinate dialkyl aluminum complexes, ortho -C 6 H 4 (NAr‘)(CH NAr‘ ‘)AlMe 2 [Ar‘ = Ar‘ ‘ = 2,6- i Pr 2 C 6 H 3 ( 3a ); Ar‘ = Ar‘ ‘ = 2,6-Me 2 C 6 H 3 ( 3b ); Ar‘ = p -MeC 6 H 4, Ar‘ ‘ = 2,6- i Pr 2 C 6 H 3 ( 3c ); Ar‘ = Ar‘ ‘ = p -MeC 6 H 4 ( 3d )], are described. Complexes 3a − d were synthesized from the reaction of AlMe 3 with the corresponding ligand at room temperature by alkane elimination. All complexes were characterized by 1 H and 13 C NMR spectroscopy, and the molecular structures of complexes 3a, 3c, and 3d were determined by X-ray crystallography. Luminescent properties of the ligands 2a − d and the complexes 3a − d in solution were studied, and it was found that emission maxima of 3a − d are in the range 519−582 nm, depending on the substituents on the aryl rings of their ligands. Complexes 3a − d exhibit intense photoluminescence in the solid state, and the maximum emission wavelengths at room temperature are in the range 532−552 nm.