[(Ph)2nacnac]MCl2(THF)2 (M = Ti, V, Cr): A New Class of Homogeneous Olefin Polymerization Catalysts Featuring β-Diiminate Ligands

[(Ph) 2 nacnac]MCl 2 (THF) 2 ([(Ph) 2 nacnac] = N, N -diphenyl-2,4-pentanediimine anion; M = Ti ( 1a ), V ( 1b ), Cr ( 1c )) were prepared and their structures determined by X-ray diffraction. In the presence of excess methylaluminoxane (MAO), 1a − c catalyzed the homopolymerization of ethylene and the copolymerization of ethylene with α-olefins.