Dialkylaluminum complexes with chelating anilido-imine ligands: Synthesis, structures, and luminescent properties

Syntheses of three new chelating anilido-imine conjugal-led ligands, ortho-C6H4(NHAr')(CH=NAr) [Ar' = Ar = 2,6-Me2C6H3 (2b); Ar' = p-MeC6B4, Ar = 2,6-(Pr2C6H3)-Pr-i (2c); Ar' = Ar = p-MeC6H4 (2d)], as well as their four-coordinate dialkyl aluminum complexes, ortho-C6H4(NAr')(CH=NAr)AlMe2 [Ar'= Ar = 2,6-(Pr2C6H3)-Pr-i (3a); Ar'= Ar = 2,6-Me2C6H3 (3b); Ar' = p-MeC6H4, Ar = 2,6-(Pr2C6H3)-Pr-i (3c); Ar' = Ar = p-MeC6H4 (3d.)], are described. Complexes 3a-d were synthesized from the reaction of AlMe3 with the corresponding ligand at room temperature by alkane elimination. All complexes were characterized by H-1 and C-13 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.