Chelating Diamide Group IV Metal Olefin Polymerization Catalysts

The novel group IV metal chelating diamide complexes [(2,6-diisopropylanilido)B(NMe 2 )B(NMe 2 )(2,6-diisopropylanilido)]MX 2, 7a (M = Ti, X = Cl), 7b (M = Ti, X = Me), and 8 (M = Zr, X = CH 2 Ph), have been prepared and characterized by 1 H and 13 C{H} NMR spectroscopy and single-crystal X-ray structure analysis ( 7a ). These complexes are active polymerization catalysts upon combining with the appropriate activator. The catalyst efficiencies, however, are considerably lower than those of Cp-based catalysts. The molecular weights of the polymers produced are activator dependent, and the polydispersities were found to be broader than those observed for Cp-based single-site catalytic systems.