Formation of organopalladium complexes via C-Br and C-C bond activation. Application in C-C and C-N coupling reactions

摘要

Reaction of [Pd_2(dba)_3] (dba = dibenzylideneacetone) with two Schiff base ligands (L~1 and L~2), derived from the condensation of 8-aminoquinoline with 2-bromobenzaldehyde or 2-bromoacetophenone, in refluxing tert-butanol afforded two organopalladium complexes 1 and 2. Crystal structure of complex 1 has been determined by X-ray diffraction studies. Structure of complex 2 has been optimized by DFT method. In both the complexes the imine ligands are coordinated, via C-Br bond activation, as tridentate CNN-donor and the fourth coordination position is occupied by an acetylide ion provided by an outgoing dba ligand via C-C bond cleavage. Both the complexes display intense absorptions in the visible and ultraviolet regions. Both the complexes catalyze C-C and C-N coupling reactions efficiently.